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en/application-dev/reference/apis/js-apis-buffer.md
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# Buffer
> **NOTE**
>
> The initial APIs of this module are supported since API version 9. Newly added APIs will be marked with a superscript to indicate their earliest API version.
A **Buffer** object represents a byte sequence of a fixed length. It is used to store binary data.
A **Buffer** object represents a fixed-length sequence of bytes. It is used to store binary data.
You can use the APIs provided by the **Buffer** module to process images and a large amount of binary data, receive and upload files, and use network protocols.
You can use the APIs provided by the **Buffer** module to process images and a large amount of binary data, and receive or upload files.
## Modules to Import
......@@ -52,7 +53,7 @@ let buf3 = buffer.alloc(11, 'aGVsbG8gd29ybGQ=', 'base64');
allocUninitializedFromPool(size: number): Buffer
Allocates a **Buffer** instance of the specified size from the buffer pool, without initializing it.
To initialize the **Buffer** instance, call the **fill()** function.
To initialize the **Buffer** instance, call **fill()**.
**System capability**: SystemCapability.Utils.Lang
......@@ -108,7 +109,7 @@ buf.fill(0);
### byteLength
byteLength(string: string | Buffer | TypeArray | DataView | ArrayBuffer | SharedArrayBuffer, encoding?: BufferEncoding): number
byteLength(string: string | Buffer | TypedArray | DataView | ArrayBuffer | SharedArrayBuffer, encoding?: BufferEncoding): number
Obtains the number of bytes of a string based on the encoding format.
......@@ -118,7 +119,7 @@ Obtains the number of bytes of a string based on the encoding format.
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| string | string \| Buffer \| TypeArray \| DataView \| ArrayBuffer \| SharedArrayBuffer | Yes| Target string.|
| string | string \| Buffer \| TypedArray \| DataView \| ArrayBuffer \| SharedArrayBuffer | Yes| Target string.|
| encoding | BufferEncoding | No| Encoding format. The default value is **utf-8**.|
**Return value**
......@@ -133,15 +134,15 @@ Obtains the number of bytes of a string based on the encoding format.
import buffer from '@ohos.buffer';
let str = '\u00bd + \u00bc = \u00be';
console.log('${str}: ${str.length} characters, ${buffer.byteLength(str, 'utf-8')} bytes');
console.log(`${str}: ${str.length} characters, ${buffer.byteLength(str, 'utf-8')} bytes`);
// Print: ½ + ¼ = ¾: 9 characters, 12 bytes
```
### compare
compare(buf1: Buffer | Uint8Array, buf2: Buffer | Uint8Array): number
compare(buf1: Buffer | Uint8Array, buf2: Buffer | Uint8Array): -1 | 0 | 1
Compares two **Buffer** instances.
Compares two **Buffer** instances. This API is used for sorting **Buffer** instances.
**System capability**: SystemCapability.Utils.Lang
......@@ -157,7 +158,7 @@ Compares two **Buffer** instances.
| Type| Description|
| -------- | -------- |
| number | Returns **0** if **buf1** is the same as **buf2**.<br>Returns **1** if **buf1** comes after **buf2** when sorted.<br>Returns **-1** if **buf1** comes before **buf2** when sorted.|
| -1&nbsp;\|&nbsp;0&nbsp;\|&nbsp;1 | Returns **0** if **buf1** is the same as **buf2**.<br>Returns **1** if **buf1** comes after **buf2** when sorted.<br>Returns **-1** if **buf1** comes before **buf2** when sorted.|
**Example**
......@@ -166,8 +167,9 @@ import buffer from '@ohos.buffer';
let buf1 = buffer.from('1234');
let buf2 = buffer.from('0123');
let res = buf1.compare(buf2);
console.log(buf1.compare(buf2));
console.log(Number(res).toString());
// Print 1
```
......@@ -200,12 +202,12 @@ import buffer from '@ohos.buffer';
let buf1 = buffer.from("1234");
let buf2 = buffer.from("abcd");
let buf = buffer.concat([buf1, buf2]);
console.log(buf); // <Buffer 31 32 33 34 61 62 63 64>
console.log(buf.toString('hex')); // 3132333461626364
```
### from
from(array: number[]): Buffer
from(array: number[]): Buffer;
Creates a **Buffer** instance with the specified array.
......@@ -228,11 +230,8 @@ Creates a **Buffer** instance with the specified array.
```ts
import buffer from '@ohos.buffer';
let arrayList = new ArrayList();
let buf = buffer.from([0x62, 0x75, 0x66, 0x66, 0x65, 0x72]);
console.log(buf);
// Print: <Buffer 62 75 66 66 65 72>
console.log(buf.toString('hex')); // 627566666572
```
### from
......@@ -268,7 +267,7 @@ let buf = buffer.from(ab, 0, 2);
### from
from(data: Buffer | Uint8Array): Buffer
from(buffer: Buffer | Uint8Array): Buffer
Creates a **Buffer** instance with the copy of another instance.
......@@ -278,7 +277,7 @@ Creates a **Buffer** instance with the copy of another instance.
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| data | Buffer&nbsp;\|&nbsp;Uint8Array | Yes| Instance to copy.|
| buffer | Buffer&nbsp;\|&nbsp;Uint8Array | Yes| **Buffer** instance to copy. |
**Return value**
......@@ -327,7 +326,7 @@ let buf = buffer.from(new String('this is a test'));
### from
from(string: string, encoding?: BufferEncoding): Buffer
from(string: String, encoding?: BufferEncoding): Buffer
Creates a **Buffer** instance based on a string in the given encoding format.
......@@ -337,7 +336,7 @@ Creates a **Buffer** instance based on a string in the given encoding format.
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| string | string | Yes| String.|
| string | String | Yes| String.|
| encoding | BufferEncoding | No| Encoding format of the string. The default value is **utf-8**.|
**Return value**
......@@ -403,7 +402,7 @@ Checks whether the encoding format is supported.
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| encoding | string | Yes| Encoding format.|
| encoding | string | Yes| Encoding format to check. |
**Return value**
......@@ -416,10 +415,10 @@ Checks whether the encoding format is supported.
```ts
import buffer from '@ohos.buffer';
console.log (Buffer.isEncoding ('utf-8')); // Print: true
console.log (Buffer.isEncoding ('hex')); // Print: true
console.log (Buffer.isEncoding ('utf/8')); // Print: false
console.log (Buffer.isEncoding ('')); // Print: false
console.log(buffer.isEncoding('utf-8').toString()); // Print: true
console.log(buffer.isEncoding('hex').toString()); // Print: true
console.log(buffer.isEncoding('utf/8').toString()); // Print: false
console.log(buffer.isEncoding('').toString()); // Print: false
```
### compare
......@@ -436,13 +435,15 @@ Compares this **Buffer** instance with another instance.
| -------- | -------- | -------- | -------- |
| target | Buffer&nbsp;\|&nbsp;Uint8Array | Yes| Target **Buffer** instance to compare.|
| targetStart | number | No| Offset to the start of the data to compare in the target **Buffer** instance. The default value is **0**.|
| targetEnd | number | No| Offset to the end of the data to compare in the target **Buffer** instance (not inclusive). The default value is length of the target **Buffer** instance.|
| targetEnd | number | No| Offset to the end of the data to compare in the target **Buffer** instance (not inclusive). The default value is the length of the target **Buffer** instance.|
| sourceStart | number | No| Offset to the start of the data to compare in this **Buffer** instance. The default value is **0**.|
| sourceEnd | number | No| Offset to the end of the data to compare in this **Buffer** instance (not inclusive). The default value is the length of this **Buffer** instance.|
**Return value**
| Type| Description|
| -------- | -------- |
| number | Returns **0** if the two **Buffer** instances are the same.<br>Returns **1** if the target instance comes before this instance when sorted.<br>Returns **-1** if the target instance comes after this instance when sorted.|
| number | Returns **0** if the two **Buffer** instances are the same.<br>Returns **1** if this instance comes after the target instance when sorted.<br>Returns **-1** if this instance comes before the target instance when sorted. |
**Example**
......@@ -452,9 +453,9 @@ import buffer from '@ohos.buffer';
let buf1 = buffer.from([1, 2, 3, 4, 5, 6, 7, 8, 9]);
let buf2 = buffer.from([5, 6, 7, 8, 9, 1, 2, 3, 4]);
console.log (buf1.compare (buf2, 5, 9, 0, 4); // Print: 0
console.log (buf1.compare (buf2, 0, 6, 4); // Print: -1
console.log (buf1.compare (buf2, 5, 6, 5)); // Print: 1
console.log(buf1.compare(buf2, 5, 9, 0, 4).toString()); // Print: 0
console.log(buf1.compare(buf2, 0, 6, 4).toString()); // Print: -1
console.log(buf1.compare(buf2, 5, 6, 5).toString()); // Print: 1
```
### copy
......@@ -512,13 +513,13 @@ import buffer from '@ohos.buffer';
let buf = buffer.from('buffer');
for (let pair of buf.entries()) {
console.log(pair);
console.log(pair.toString());
}
```
### equals
equals(otherBuffer: Buffer | Uint8Array): boolean
equals(otherBuffer: Uint8Array | Buffer): boolean
Checks whether this **Buffer** instance is the same as another **Buffer** instance.
......@@ -528,7 +529,7 @@ Checks whether this **Buffer** instance is the same as another **Buffer** instan
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| otherBuffer | Buffer&nbsp;\|&nbsp;Uint8Array | Yes| **Buffer** instance to compare.|
| otherBuffer | Uint8Array&nbsp;\|&nbsp;Buffer | Yes| **Buffer** instance to compare.|
**Return value**
......@@ -545,8 +546,8 @@ let buf1 = buffer.from('ABC');
let buf2 = buffer.from('414243', 'hex');
let buf3 = buffer.from('ABCD');
console.log (buf1.equals (buf2)); // Print: true
console.log (buf1.equals (buf3)); // Print: false
console.log(buf1.equals(buf2).toString()); // Print: true
console.log(buf1.equals(buf3).toString()); // Print: false
```
......@@ -596,7 +597,7 @@ Checks whether this **Buffer** instance contains the specified value.
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| value | string&nbsp;\|&nbsp;number&nbsp;\|&nbsp;Buffer&nbsp;\|&nbsp;Uint8Array | Yes| Value to match.|
| byteOffset | number | No| Number of bytes to skip before checking data. If the offset is a negative number, data is searched from the end of the **Buffer** instance. The default value is **0**.|
| byteOffset | number | No| Number of bytes to skip before starting to check data. If the offset is a negative number, data is checked from the end of the **Buffer** instance. The default value is **0**. |
| encoding | BufferEncoding | No| Encoding format used if **value** is a string. The default value is **utf-8**.|
**Return value**
......@@ -611,8 +612,8 @@ Checks whether this **Buffer** instance contains the specified value.
import buffer from '@ohos.buffer';
let buf = buffer.from('this is a buffer');
console.log (buf.includes ('this')); // Print: true
console.log (buf.includes ('be')); // Print: false
console.log(buf.includes('this').toString()); // Print: true
console.log(buf.includes('be').toString()); // Print: false
```
### indexOf
......@@ -628,7 +629,7 @@ Obtains the index of the first occurrence of the specified value in this **Buffe
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| value | string&nbsp;\|&nbsp;number&nbsp;\|&nbsp;Buffer&nbsp;\|&nbsp;Uint8Array | Yes| Value to match.|
| byteOffset | number | No| Number of bytes to skip before checking data. If the offset is a negative number, data is searched from the end of the **Buffer** instance. The default value is **0**.|
| byteOffset | number | No| Number of bytes to skip before starting to check data. If the offset is a negative number, data is checked from the end of the **Buffer** instance. The default value is **0**. |
| encoding | BufferEncoding | No| Encoding format used if **value** is a string. The default value is **utf-8**.|
**Return value**
......@@ -643,8 +644,8 @@ Obtains the index of the first occurrence of the specified value in this **Buffe
import buffer from '@ohos.buffer';
let buf = buffer.from('this is a buffer');
console.log (buf.indexOf('this')); // Print: 0
console.log(buf.indexOf('is')); // Print: 2
console.log(buf.indexOf('this').toString()); // Print: 0
console.log(buf.indexOf('is').toString()); // Print: 2
```
### keys
......@@ -668,7 +669,7 @@ import buffer from '@ohos.buffer';
let buf = buffer.from('buffer');
for (const key of buf.keys()) {
console.log(key);
console.log(key.toString());
}
```
......@@ -685,7 +686,7 @@ Obtains the index of the last occurrence of the specified value in this **Buffer
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| value | string&nbsp;\|&nbsp;number&nbsp;\|&nbsp;Buffer&nbsp;\|&nbsp;Uint8Array | Yes| Value to match.|
| byteOffset | number | No| Number of bytes to skip before checking data. If the offset is a negative number, data is searched from the end of the **Buffer** instance. The default value is **0**.|
| byteOffset | number | No| Number of bytes to skip before starting to check data. If the offset is a negative number, data is checked from the end of the **Buffer** instance. The default value is **0**. |
| encoding | BufferEncoding | No| Encoding format used if **value** is a string. The default value is **utf-8**.|
**Return value**
......@@ -700,16 +701,16 @@ Obtains the index of the last occurrence of the specified value in this **Buffer
import buffer from '@ohos.buffer';
let buf = buffer.from('this buffer is a buffer');
console.log(buf.lastIndexOf('this')); // Print: 0
console.log(buf.lastIndexOf('buffer')); // Print:17
console.log(buf.lastIndexOf('this').toString()); // Print: 0
console.log(buf.lastIndexOf('buffer').toString()); // Print: 17
```
### readBigInt64BE
readBigInt64BE(offset: number): number
readBigInt64BE(offset?: number): bigint
Reads a signed, big-endian 64-bit integer from this **Buffer** instance at the specified offset.
Reads a signed, big-endian 64-bit Big integer from this **Buffer** instance at the specified offset.
**System capability**: SystemCapability.Utils.Lang
......@@ -717,13 +718,13 @@ Reads a signed, big-endian 64-bit integer from this **Buffer** instance at the s
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| offset | number | Yes| Number of bytes to skip before reading data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to read data. The default value is **0**.|
**Return value**
| Type| Description|
| -------- | -------- |
| number | A signed, big-endian 64-bit integer.|
| bigint | A signed, big-endian 64-bit Big integer. |
**Example**
......@@ -732,14 +733,14 @@ import buffer from '@ohos.buffer';
let buf = buffer.from([0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x70,
0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78]);
console.log(buf.readBigInt64BE(0));
console.log(buf.readBigInt64BE(0).toString());
```
### readBigInt64LE
readBigInt64LE(offset: number): number
readBigInt64LE(offset?: number): bigint
Reads a signed, little-endian 64-bit integer from this **Buffer** instance at the specified offset.
Reads a signed, little-endian 64-bit Big integer from this **Buffer** instance at the specified offset.
**System capability**: SystemCapability.Utils.Lang
......@@ -747,13 +748,13 @@ Reads a signed, little-endian 64-bit integer from this **Buffer** instance at th
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| offset | number | Yes| Number of bytes to skip before reading data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to read data. The default value is **0**.|
**Return value**
| Type| Description|
| -------- | -------- |
| number | A signed, little-endian 64-bit integer.|
| bigint | A signed, little-endian 64-bit Big integer. |
**Example**
......@@ -762,14 +763,14 @@ import buffer from '@ohos.buffer';
let buf = buffer.from([0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x70,
0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78]);
console.log(buf.readBigInt64LE(0));
console.log(buf.readBigInt64LE(0).toString());
```
### readBigUInt64BE
readBigUInt64BE(offset: number): number
readBigUInt64BE(offset?: number): bigint
Reads an unsigned, big-endian 64-bit integer from this **Buffer** instance at the specified offset.
Reads an unsigned, big-endian 64-bit Big integer from this **Buffer** instance at the specified offset.
**System capability**: SystemCapability.Utils.Lang
......@@ -777,13 +778,13 @@ Reads an unsigned, big-endian 64-bit integer from this **Buffer** instance at th
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| offset | number | Yes| Number of bytes to skip before reading data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to read data. The default value is **0**.|
**Return value**
| Type| Description|
| -------- | -------- |
| number | An unsigned, big-endian 64-bit integer.|
| bigint | An unsigned, big-endian 64-bit Big integer. |
**Example**
......@@ -792,14 +793,14 @@ import buffer from '@ohos.buffer';
let buf = buffer.from([0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x70,
0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78]);
console.log(buf.readBigUInt64BE(0));
console.log(buf.readBigUInt64BE(0).toString());
```
### readBigUInt64LE
readBigUInt64LE(offset: number): number
readBigUInt64LE(offset?: number): bigint
Reads an unsigned, little-endian 64-bit integer from this **Buffer** instance at the specified offset.
Reads an unsigned, little-endian 64-bit Big integer from this **Buffer** instance at the specified offset.
**System capability**: SystemCapability.Utils.Lang
......@@ -807,13 +808,13 @@ Reads an unsigned, little-endian 64-bit integer from this **Buffer** instance at
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| offset | number | Yes| Number of bytes to skip before reading data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to read data. The default value is **0**.|
**Return value**
| Type| Description|
| -------- | -------- |
| number | An unsigned, little-endian 64-bit integer.|
| bigint | An unsigned, little-endian 64-bit Big integer. |
**Example**
......@@ -822,14 +823,14 @@ import buffer from '@ohos.buffer';
let buf = buffer.from([0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x70,
0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78]);
console.log(buf.readBigUInt64LE(0));
console.log(buf.readBigUInt64LE(0).toString());
```
### readDoubleBE
readDoubleBE(offset: number): number
readDoubleBE(offset?: number): number
Reads a 64-bit, big-endian double-precision floating-point number from this **Buffer** instance at the specified offset.
Reads a big-endian double-precision floating-point number from this **Buffer** instance at the specified offset.
**System capability**: SystemCapability.Utils.Lang
......@@ -837,13 +838,13 @@ Reads a 64-bit, big-endian double-precision floating-point number from this **Bu
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| offset | number | Yes| Number of bytes to skip before reading data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to read data. The default value is **0**.|
**Return value**
| Type| Description|
| -------- | -------- |
| number | A 64-bit, big-endian double-precision floating-point number.|
| number | A big-endian double-precision floating-point number. |
**Example**
......@@ -851,14 +852,14 @@ Reads a 64-bit, big-endian double-precision floating-point number from this **Bu
import buffer from '@ohos.buffer';
let buf = buffer.from([1, 2, 3, 4, 5, 6, 7, 8]);
console.log(buf.readDoubleBE(0));
console.log(buf.readDoubleBE(0).toString());
```
### readDoubleLE
readDoubleLE(offset: number): number
readDoubleLE(offset?: number): number
Reads a 64-bit, little-endian double-precision floating-point number from this **Buffer** instance at the specified offset.
Reads a little-endian double-precision floating-point number from this **Buffer** instance at the specified offset.
**System capability**: SystemCapability.Utils.Lang
......@@ -866,13 +867,13 @@ Reads a 64-bit, little-endian double-precision floating-point number from this *
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| offset | number | Yes| Number of bytes to skip before reading data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to read data. The default value is **0**.|
**Return value**
| Type| Description|
| -------- | -------- |
| number | A 64-bit, little-endian double-precision floating-point number.|
| number | A little-endian double-precision floating-point number. |
**Example**
......@@ -880,14 +881,14 @@ Reads a 64-bit, little-endian double-precision floating-point number from this *
import buffer from '@ohos.buffer';
let buf = buffer.from([1, 2, 3, 4, 5, 6, 7, 8]);
console.log(buf.readDoubleLE(0));
console.log(buf.readDoubleLE(0).toString());
```
### readFloatBE
readFloatBE(offset: number): number
readFloatBE(offset?: number): number
Reads a 32-bit, big-endian floating-point number from this **Buffer** instance at the specified offset.
Reads a big-endian single-precision floating-point number from this **Buffer** instance at the specified offset.
**System capability**: SystemCapability.Utils.Lang
......@@ -895,13 +896,13 @@ Reads a 32-bit, big-endian floating-point number from this **Buffer** instance a
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| offset | number | Yes| Number of bytes to skip before reading data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to read data. The default value is **0**.|
**Return value**
| Type| Description|
| -------- | -------- |
| number | A 32-bit, big-endian floating-point number.|
| number | A big-endian single-precision floating-point number. |
**Example**
......@@ -909,14 +910,14 @@ Reads a 32-bit, big-endian floating-point number from this **Buffer** instance a
import buffer from '@ohos.buffer';
let buf = buffer.from([1, 2, 3, 4, 5, 6, 7, 8]);
console.log(buf.readFloatBE(0));
console.log(buf.readFloatBE(0).toString());
```
### readFloatLE
readFloatLE(offset: number): number
readFloatLE(offset?: number): number
Reads a 32-bit, little-endian floating-point number from this **Buffer** instance at the specified offset.
Reads a little-endian single-precision floating-point number from this **Buffer** instance at the specified offset.
**System capability**: SystemCapability.Utils.Lang
......@@ -924,13 +925,13 @@ Reads a 32-bit, little-endian floating-point number from this **Buffer** instanc
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| offset | number | Yes| Number of bytes to skip before reading data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to read data. The default value is **0**.|
**Return value**
| Type| Description|
| -------- | -------- |
| number | A 32-bit, little-endian floating-point number.|
| number | A little-endian single-precision floating-point number. |
**Example**
......@@ -938,12 +939,12 @@ Reads a 32-bit, little-endian floating-point number from this **Buffer** instanc
import buffer from '@ohos.buffer';
let buf = buffer.from([1, 2, 3, 4, 5, 6, 7, 8]);
console.log(buf.readFloatLE(0));
console.log(buf.readFloatLE(0).toString());
```
### readInt8
readInt8(offset: number): number
readInt8(offset?: number): number
Reads a signed 8-bit integer from this **Buffer** instance at the specified offset.
......@@ -953,13 +954,13 @@ Reads a signed 8-bit integer from this **Buffer** instance at the specified offs
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| offset | number | Yes| Number of bytes to skip before reading data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to read data. The default value is **0**.|
**Return value**
| Type| Description|
| -------- | -------- |
| number | A signed 8-bit integer.|
| number | A signed 8-bit integer. |
**Example**
......@@ -967,13 +968,13 @@ Reads a signed 8-bit integer from this **Buffer** instance at the specified offs
import buffer from '@ohos.buffer';
let buf = buffer.from([-1, 5]);
console.log (buf.readInt8(0)); // Print: -1
console.log (buf.readInt8(1); // Print: 5
console.log(buf.readInt8(0).toString()); // Print: -1
console.log(buf.readInt8(1).toString()); // Print: 5
```
### readInt16BE
readInt16BE(offset: number): number
readInt16BE(offset?: number): number
Reads a signed, big-endian 16-bit integer from this **Buffer** instance at the specified offset.
......@@ -983,7 +984,7 @@ Reads a signed, big-endian 16-bit integer from this **Buffer** instance at the s
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| offset | number | Yes| Number of bytes to skip before reading data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to read data. The default value is **0**.|
**Return value**
......@@ -996,13 +997,13 @@ Reads a signed, big-endian 16-bit integer from this **Buffer** instance at the s
```ts
import buffer from '@ohos.buffer';
let buf = Buffer.from([0, 5]);
console.log (buf.readInt16BE(0)); // Print: 5
let buf = buffer.from([0, 5]);
console.log(buf.readInt16BE(0).toString()); // Print: 5
```
### readInt16LE
readInt16LE(offset: number): number
readInt16LE(offset?: number): number
Reads a signed, little-endian 16-bit integer from this **Buffer** instance at the specified offset.
......@@ -1012,7 +1013,7 @@ Reads a signed, little-endian 16-bit integer from this **Buffer** instance at th
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| offset | number | Yes| Number of bytes to skip before reading data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to read data. The default value is **0**.|
**Return value**
......@@ -1025,13 +1026,13 @@ Reads a signed, little-endian 16-bit integer from this **Buffer** instance at th
```ts
import buffer from '@ohos.buffer';
let buf = Buffer.from([0, 5]);
console.log (buf.readInt16BE(0)); // Print: 1280
let buf = buffer.from([0, 5]);
console.log(buf.readInt16LE(0).toString()); // Print: 1280
```
### readInt32BE
readInt32BE(offset: number): number
readInt32BE(offset?: number): number
Reads a signed, big-endian 32-bit integer from this **Buffer** instance at the specified offset.
......@@ -1041,7 +1042,7 @@ Reads a signed, big-endian 32-bit integer from this **Buffer** instance at the s
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| offset | number | Yes| Number of bytes to skip before reading data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to read data. The default value is **0**.|
**Return value**
......@@ -1055,12 +1056,12 @@ Reads a signed, big-endian 32-bit integer from this **Buffer** instance at the s
import buffer from '@ohos.buffer';
let buf = buffer.from([0, 0, 0, 5]);
console.log(buf.readInt32BE(0)); // Print: 5
console.log(buf.readInt32BE(0).toString()); // Print: 5
```
### readInt32LE
readInt32LE(offset: number): number
readInt32LE(offset?: number): number
Reads a signed, little-endian 32-bit integer from this **Buffer** instance at the specified offset.
......@@ -1070,7 +1071,7 @@ Reads a signed, little-endian 32-bit integer from this **Buffer** instance at th
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| offset | number | Yes| Number of bytes to skip before reading data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to read data. The default value is **0**.|
**Return value**
......@@ -1084,7 +1085,7 @@ Reads a signed, little-endian 32-bit integer from this **Buffer** instance at th
import buffer from '@ohos.buffer';
let buf = buffer.from([0, 0, 0, 5]);
console.log (buf.readInt32LE(0)); // Print: 83886080
console.log(buf.readInt32LE(0).toString()); // Print: 83886080
```
### readIntBE
......@@ -1099,8 +1100,8 @@ Reads the specified number of bytes from this **Buffer** instance at the specifi
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| offset | number | No| Number of bytes to skip before reading data. The default value is **0**.|
| byteLength | number | No| Number of bytes to read.|
| offset | number | Yes| Number of bytes to skip before starting to read data. The default value is **0**.|
| byteLength | number | Yes| Number of bytes to read.|
**Return value**
......@@ -1114,9 +1115,9 @@ Reads the specified number of bytes from this **Buffer** instance at the specifi
```ts
import buffer from '@ohos.buffer';
let buf = Buffer.from("ab");
let buf = buffer.from("ab");
let num = buf.readIntBE(0, 1);
console.log(num); // 97
console.log(num.toString()); // 97
```
......@@ -1132,8 +1133,8 @@ Reads the specified number of bytes from this **Buffer** instance at the specifi
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| offset | number | No| Number of bytes to skip before reading data. The default value is **0**.|
| byteLength | number | No| Number of bytes to read.|
| offset | number | Yes| Number of bytes to skip before starting to read data. The default value is **0**.|
| byteLength | number | Yes| Number of bytes to read.|
**Return value**
......@@ -1153,7 +1154,7 @@ console.log(buf.readIntLE(0, 6).toString(16));
### readUInt8
readUInt8(offset: number): number
readUInt8(offset?: number): number
Reads an unsigned 8-bit integer from this **Buffer** instance at the specified offset.
......@@ -1163,7 +1164,7 @@ Reads an unsigned 8-bit integer from this **Buffer** instance at the specified o
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| offset | number | No| Number of bytes to skip before reading data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to read data. The default value is **0**.|
**Return value**
......@@ -1178,13 +1179,13 @@ Reads an unsigned 8-bit integer from this **Buffer** instance at the specified o
import buffer from '@ohos.buffer';
let buf = buffer.from([1, -2]);
console.log(buf.readUInt8(0));
console.log(buf.readUInt8(1));
console.log(buf.readUInt8(0).toString());
console.log(buf.readUInt8(1).toString());
```
### readUInt16BE
readUInt16BE(offset: number): number
readUInt16BE(offset?: number): number
Reads an unsigned, big-endian 16-bit integer from this **Buffer** instance at the specified offset.
......@@ -1194,7 +1195,7 @@ Reads an unsigned, big-endian 16-bit integer from this **Buffer** instance at th
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| offset | number | No| Number of bytes to skip before reading data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to read data. The default value is **0**.|
**Return value**
......@@ -1215,7 +1216,7 @@ console.log(buf.readUInt16BE(1).toString(16));
### readUInt16LE
readUInt16LE(offset: number): number
readUInt16LE(offset?: number): number
Reads an unsigned, little-endian 16-bit integer from this **Buffer** instance at the specified offset.
......@@ -1225,7 +1226,7 @@ Reads an unsigned, little-endian 16-bit integer from this **Buffer** instance at
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| offset | number | No| Number of bytes to skip before reading data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to read data. The default value is **0**.|
**Return value**
......@@ -1246,7 +1247,7 @@ console.log(buf.readUInt16LE(1).toString(16));
### readUInt32BE
readUInt32BE(offset: number): number
readUInt32BE(offset?: number): number
Reads an unsigned, big-endian 32-bit integer from this **Buffer** instance at the specified offset.
......@@ -1256,7 +1257,7 @@ Reads an unsigned, big-endian 32-bit integer from this **Buffer** instance at th
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| offset | number | No| Number of bytes to skip before reading data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to read data. The default value is **0**.|
**Return value**
......@@ -1276,7 +1277,7 @@ console.log(buf.readUInt32BE(0).toString(16));
### readUInt32LE
readUInt32LE(offset: number): number
readUInt32LE(offset?: number): number
Reads an unsigned, little-endian 32-bit integer from this **Buffer** instance at the specified offset.
......@@ -1286,7 +1287,7 @@ Reads an unsigned, little-endian 32-bit integer from this **Buffer** instance at
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| offset | number | No| Number of bytes to skip before reading data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to read data. The default value is **0**.|
**Return value**
......@@ -1316,8 +1317,8 @@ Reads the specified number of bytes from this **Buffer** instance at the specifi
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| offset | number | No| Number of bytes to skip before reading data. The default value is **0**.|
| byteLength | number | No| Number of bytes to read.|
| offset | number | Yes| Number of bytes to skip before starting to read data. The default value is **0**.|
| byteLength | number | Yes| Number of bytes to read.|
**Return value**
......@@ -1347,8 +1348,8 @@ Reads the specified number of bytes from this **Buffer** instance at the specifi
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| offset | number | No| Number of bytes to skip before reading data. The default value is **0**.|
| byteLength | number | No| Number of bytes to read.|
| offset | number | Yes| Number of bytes to skip before starting to read data. The default value is **0**.|
| byteLength | number | Yes| Number of bytes to read.|
**Return value**
......@@ -1423,10 +1424,10 @@ Interprets this **Buffer** instance as an array of unsigned 16-bit integers and
import buffer from '@ohos.buffer';
let buf1 = buffer.from([0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8]);
console.log(buf1); // Print: <Buffer 01 02 03 04 05 06 07 08>
console.log(buf1.toString('hex')); // Print: 0102030405060708
buf1.swap16();
console.log(buf1); // Print: <Buffer 02 01 04 03 06 05 08 07>
console.log(buf1.toString('hex')); // Print: 0201040306050807
```
### swap32
......@@ -1450,10 +1451,10 @@ Interprets this **Buffer** instance as an array of unsigned 32-bit integers and
import buffer from '@ohos.buffer';
let buf1 = buffer.from([0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8]);
console.log(buf1); // Print: <Buffer 01 02 03 04 05 06 07 08>
console.log(buf1.toString('hex')); // Print: 0102030405060708
buf1.swap32();
console.log(buf1); // Print: <Buffer 04 03 02 01 08 07 06 05>
console.log(buf1.toString('hex')); // Print: 0403020108070605
```
### swap64
......@@ -1477,9 +1478,9 @@ Interprets this **Buffer** instance as an array of unsigned 64-bit integers and
import buffer from '@ohos.buffer';
let buf1 = buffer.from([0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8]);
console.log(buf1); // Print: <Buffer 01 02 03 04 05 06 07 08>
console.log(buf1.toString('hex')); // Print: 0102030405060708
buf1.swap64();
console.log(buf1); // Print: <Buffer 08 07 06 05 04 03 02 01>
console.log(buf1.toString('hex')); // Print: 0807060504030201
```
### toJSON
......@@ -1503,9 +1504,8 @@ Converts this **Buffer** instance into a JSON object.
import buffer from '@ohos.buffer';
let buf1 = buffer.from([0x1, 0x2, 0x3, 0x4, 0x5]);
let buf2 = buffer.from(buf1.toJSON())
let json = JSON.stringify(buf2);
console.log(json);
let obj = buf1.toJSON();
console.log(JSON.stringify(obj))
// Print: {"type":"Buffer","data":[1,2,3,4,5]}
```
......@@ -1564,8 +1564,8 @@ Creates and returns an iterator that contains the values of this **Buffer** inst
import buffer from '@ohos.buffer';
let buf1 = buffer.from('buffer');
for (const value of buf.values()) {
console.log(value);
for (let value of buf1.values()) {
console.log(value.toString());
}
```
......@@ -1582,7 +1582,7 @@ Writes a string of the specified length to this **Buffer** instance at the speci
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| str | string | Yes| String to write.|
| offset | number | No| Number of bytes to skip before writing data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to write data. The default value is **0**.|
| length | number | No| Maximum number of bytes to write. The default value is the length of the **Buffer** instance minus the offset.|
| encoding | BufferEncoding | No| Encoding format of the string. The default value is **utf-8**.|
......@@ -1603,15 +1603,15 @@ let len = buf.write('\u00bd + \u00bc = \u00be', 0);
console.log(`${len} bytes: ${buf.toString('utf-8', 0, len)}`);
// Print: 12 bytes: ½ + ¼ = ¾
let buffer = Buffer.alloc(10);
let length = buffer.write('abcd', 8);
let buffer1 = buffer.alloc(10);
let length = buffer1.write('abcd', 8);
```
### writeBigInt64BE
writeBigInt64BE(value: number, offset?: number): number
writeBigInt64BE(value: bigint, offset?: number): number
Writes a signed, big-endian 64-bit integer to this **Buffer** instance at the specified offset.
Writes a signed, big-endian 64-bit Big integer to this **Buffer** instance at the specified offset.
**System capability**: SystemCapability.Utils.Lang
......@@ -1619,8 +1619,8 @@ Writes a signed, big-endian 64-bit integer to this **Buffer** instance at the sp
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| value | number | Yes| Data to write.|
| offset | number | No| Number of bytes to skip before writing data. The default value is **0**.|
| value | bigint | Yes| Data to write.|
| offset | number | No| Number of bytes to skip before starting to write data. The default value is **0**.|
**Return value**
......@@ -1640,9 +1640,9 @@ buf.writeBigInt64BE(0x0102030405060708n, 0);
### writeBigInt64LE
writeBigInt64LE(value : number, offset? : number): number
writeBigInt64LE(value: bigint, offset?: number): number
Writes a signed, little-endian 64-bit integer to this **Buffer** instance at the specified offset.
Writes a signed, little-endian 64-bit Big integer to this **Buffer** instance at the specified offset.
**System capability**: SystemCapability.Utils.Lang
......@@ -1650,8 +1650,8 @@ Writes a signed, little-endian 64-bit integer to this **Buffer** instance at the
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| value | number | Yes| Data to write.|
| offset | number | No| Number of bytes to skip before writing data. The default value is **0**.|
| value | bigint | Yes| Data to write.|
| offset | number | No| Number of bytes to skip before starting to write data. The default value is **0**.|
**Return value**
......@@ -1671,9 +1671,9 @@ buf.writeBigInt64LE(0x0102030405060708n, 0);
### writeBigUInt64BE
writeBigUInt64BE(value : number, offset? : number): number
writeBigUInt64BE(value: bigint, offset?: number): number
Writes an unsigned, big-endian 64-bit integer to this **Buffer** instance at the specified offset.
Writes an unsigned, big-endian 64-bit Big integer to this **Buffer** instance at the specified offset.
**System capability**: SystemCapability.Utils.Lang
......@@ -1681,8 +1681,8 @@ Writes an unsigned, big-endian 64-bit integer to this **Buffer** instance at the
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| value | number | Yes| Data to write.|
| offset | number | No| Number of bytes to skip before writing data. The default value is **0**.|
| value | bigint | Yes| Data to write.|
| offset | number | No| Number of bytes to skip before starting to write data. The default value is **0**.|
**Return value**
......@@ -1702,9 +1702,9 @@ buf.writeBigUInt64BE(0xdecafafecacefaden, 0);
### writeBigUInt64LE
writeBigUInt64LE(value : number, offset? : number): number
writeBigUInt64LE(value: bigint, offset?: number): number
Writes an unsigned, little-endian 64-bit integer to this **Buffer** instance at the specified offset.
Writes an unsigned, little-endian 64-bit Big integer to this **Buffer** instance at the specified offset.
**System capability**: SystemCapability.Utils.Lang
......@@ -1712,8 +1712,8 @@ Writes an unsigned, little-endian 64-bit integer to this **Buffer** instance at
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| value | number | Yes| Data to write.|
| offset | number | No| Number of bytes to skip before writing data. The default value is **0**.|
| value | bigint | Yes| Data to write.|
| offset | number | No| Number of bytes to skip before starting to write data. The default value is **0**.|
**Return value**
......@@ -1733,9 +1733,9 @@ buf.writeBigUInt64LE(0xdecafafecacefaden, 0);
### writeDoubleBE
writeDoubleBE(value : number, offset? : number): number
writeDoubleBE(value: number, offset?: number): number
Writes a 64-bit, big-endian double-precision floating-point number to this **Buffer** instance at the specified offset.
Writes a big-endian double-precision floating-point number to this **Buffer** instance at the specified offset.
**System capability**: SystemCapability.Utils.Lang
......@@ -1744,7 +1744,7 @@ Writes a 64-bit, big-endian double-precision floating-point number to this **Buf
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| value | number | Yes| Data to write.|
| offset | number | No| Number of bytes to skip before writing data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to write data. The default value is **0**.|
**Return value**
......@@ -1764,9 +1764,9 @@ buf.writeDoubleBE(123.456, 0);
### writeDoubleLE
writeDoubleLE(value : number, offset? : number): number
writeDoubleLE(value: number, offset?: number): number
Writes a 64-bit, little-endian double-precision floating-point number to this **Buffer** instance at the specified offset.
Writes a little-endian double-precision floating-point number to this **Buffer** instance at the specified offset.
**System capability**: SystemCapability.Utils.Lang
......@@ -1775,7 +1775,7 @@ Writes a 64-bit, little-endian double-precision floating-point number to this **
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| value | number | Yes| Data to write.|
| offset | number | No| Number of bytes to skip before writing data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to write data. The default value is **0**.|
**Return value**
......@@ -1795,9 +1795,9 @@ buf.writeDoubleLE(123.456, 0);
### writeFloatBE
writeFloatBE(value : number, offset? : number): number
writeFloatBE(value: number, offset?: number): number
Writes a 32-bit, big-endian floating-point number to this **Buffer** instance at the specified offset.
Writes a big-endian single-precision floating-point number to this **Buffer** instance at the specified offset.
**System capability**: SystemCapability.Utils.Lang
......@@ -1806,7 +1806,7 @@ Writes a 32-bit, big-endian floating-point number to this **Buffer** instance at
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| value | number | Yes| Data to write.|
| offset | number | No| Number of bytes to skip before writing data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to write data. The default value is **0**.|
**Return value**
......@@ -1827,9 +1827,9 @@ buf.writeFloatBE(0xcafebabe, 0);
### writeFloatLE
writeFloatLE(value : number, offset? : number): number
writeFloatLE(value: number, offset?: number): number
Writes a 32-bit, little-endian floating-point number to this **Buffer** instance at the specified offset.
Writes a little-endian single-precision floating-point number to this **Buffer** instance at the specified offset.
**System capability**: SystemCapability.Utils.Lang
......@@ -1838,7 +1838,7 @@ Writes a 32-bit, little-endian floating-point number to this **Buffer** instance
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| value | number | Yes| Data to write.|
| offset | number | No| Number of bytes to skip before writing data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to write data. The default value is **0**.|
**Return value**
......@@ -1858,7 +1858,7 @@ buf.writeFloatLE(0xcafebabe, 0);
### writeInt8
writeInt8(value : number, offset? : number): number
writeInt8(value: number, offset?: number): number
Writes a signed 8-bit integer to this **Buffer** instance at the specified offset.
......@@ -1869,7 +1869,7 @@ Writes a signed 8-bit integer to this **Buffer** instance at the specified offse
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| value | number | Yes| Data to write.|
| offset | number | No| Number of bytes to skip before writing data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to write data. The default value is **0**.|
**Return value**
......@@ -1891,7 +1891,7 @@ buf.writeInt8(-2, 1);
### writeInt16BE
writeInt16BE(value : number, offset? : number): number
writeInt16BE(value: number, offset?: number): number
Writes a signed, big-endian 16-bit integer to this **Buffer** instance at the specified offset.
......@@ -1902,7 +1902,7 @@ Writes a signed, big-endian 16-bit integer to this **Buffer** instance at the sp
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| value | number | Yes| Data to write.|
| offset | number | No| Number of bytes to skip before writing data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to write data. The default value is **0**.|
**Return value**
......@@ -1923,7 +1923,7 @@ buf.writeInt16BE(0x0102, 0);
### writeInt16LE
writeInt16LE(value : number, offset : number): number
writeInt16LE(value: number, offset?: number): number
Writes a signed, little-endian 16-bit integer to this **Buffer** instance at the specified offset.
......@@ -1934,7 +1934,7 @@ Writes a signed, little-endian 16-bit integer to this **Buffer** instance at the
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| value | number | Yes| Data to write.|
| offset | number | No| Number of bytes to skip before writing data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to write data. The default value is **0**.|
**Return value**
......@@ -1954,7 +1954,7 @@ buf.writeInt16LE(0x0304, 0);
### writeInt32BE
writeInt32BE(value : number, offset : number): number
writeInt32BE(value: number, offset?: number): number
Writes a signed, big-endian 32-bit integer to this **Buffer** instance at the specified offset.
......@@ -1965,7 +1965,7 @@ Writes a signed, big-endian 32-bit integer to this **Buffer** instance at the sp
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| value | number | Yes| Data to write.|
| offset | number | No| Number of bytes to skip before writing data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to write data. The default value is **0**.|
**Return value**
......@@ -1986,7 +1986,7 @@ buf.writeInt32BE(0x01020304, 0);
### writeInt32LE
writeInt32LE(value : number, offset : number): number
writeInt32LE(value: number, offset?: number): number
Writes a signed, little-endian 32-bit integer to this **Buffer** instance at the specified offset.
......@@ -1997,7 +1997,7 @@ Writes a signed, little-endian 32-bit integer to this **Buffer** instance at the
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| value | number | Yes| Data to write.|
| offset | number | No| Number of bytes to skip before writing data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to write data. The default value is **0**.|
**Return value**
......@@ -2017,7 +2017,7 @@ buf.writeInt32LE(0x05060708, 0);
### writeIntBE
writeIntBE(value : number, offset : number, byteLength : number): number
writeIntBE(value: number, offset: number, byteLength: number): number
Writes a big-endian signed value of the specified length to this **Buffer** instance at the specified offset.
......@@ -2028,8 +2028,8 @@ Writes a big-endian signed value of the specified length to this **Buffer** inst
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| value | number | Yes| Data to write.|
| offset | number | No| Number of bytes to skip before writing data. The default value is **0**.|
| byteLength | number | No| Number of bytes to write.|
| offset | number | Yes| Number of bytes to skip before starting to write data. The default value is **0**.|
| byteLength | number | Yes| Number of bytes to write.|
**Return value**
......@@ -2050,7 +2050,7 @@ buf.writeIntBE(0x1234567890ab, 0, 6);
### writeIntLE
writeIntLE(value : number, offset : number, byteLength : number): number
writeIntLE(value: number, offset: number, byteLength: number): number
Writes a little-endian signed value of the specified length to this **Buffer** instance at the specified offset.
......@@ -2061,8 +2061,8 @@ Writes a little-endian signed value of the specified length to this **Buffer** i
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| value | number | Yes| Data to write.|
| offset | number | No| Number of bytes to skip before writing data. The default value is **0**.|
| byteLength | number | No| Number of bytes to write.|
| offset | number | Yes| Number of bytes to skip before starting to write data. The default value is **0**.|
| byteLength | number | Yes| Number of bytes to write.|
**Return value**
......@@ -2082,7 +2082,7 @@ buf.writeIntLE(0x1234567890ab, 0, 6);
### writeUInt8
writeUInt8(value : number, offset : number): number
writeUInt8(value: number, offset?: number): number
Writes an unsigned 8-bit integer to this **Buffer** instance at the specified offset.
......@@ -2093,7 +2093,7 @@ Writes an unsigned 8-bit integer to this **Buffer** instance at the specified of
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| value | number | Yes| Data to write.|
| offset | number | No| Number of bytes to skip before writing data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to write data. The default value is **0**.|
**Return value**
......@@ -2116,7 +2116,7 @@ buf.writeUInt8(0x42, 3);
### writeUInt16BE
writeUInt16BE(value : number, offset : number): number
writeUInt16BE(value: number, offset?: number): number
Writes an unsigned, big-endian 16-bit integer to this **Buffer** instance at the specified offset.
......@@ -2127,7 +2127,7 @@ Writes an unsigned, big-endian 16-bit integer to this **Buffer** instance at the
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| value | number | Yes| Data to write.|
| offset | number | No| Number of bytes to skip before writing data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to write data. The default value is **0**.|
**Return value**
......@@ -2148,7 +2148,7 @@ buf.writeUInt16BE(0xbeef, 2);
### writeUInt16LE
writeUInt16LE(value : number, offset : number): number
writeUInt16LE(value: number, offset?: number): number
Writes an unsigned, little-endian 16-bit integer to this **Buffer** instance at the specified offset.
......@@ -2159,7 +2159,7 @@ Writes an unsigned, little-endian 16-bit integer to this **Buffer** instance at
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| value | number | Yes| Data to write.|
| offset | number | No| Number of bytes to skip before writing data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to write data. The default value is **0**.|
**Return value**
......@@ -2180,7 +2180,7 @@ buf.writeUInt16LE(0xbeef, 2);
### writeUInt32BE
writeUInt32BE(value : number, offset : number): number
writeUInt32BE(value: number, offset?: number): number
Writes an unsigned, big-endian 32-bit integer to this **Buffer** instance at the specified offset.
......@@ -2191,7 +2191,7 @@ Writes an unsigned, big-endian 32-bit integer to this **Buffer** instance at the
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| value | number | Yes| Data to write.|
| offset | number | No| Number of bytes to skip before writing data. The default value is **0**.|
| offset | number | No| Number of bytes to skip before starting to write data. The default value is **0**.|
**Return value**
......@@ -2211,7 +2211,7 @@ buf.writeUInt32BE(0xfeedface, 0);
### writeUInt32LE
writeUInt32LE(value : number, offset : number): number
writeUInt32LE(value: number, offset?: number): number
Writes an unsigned, little-endian 32-bit integer to this **Buffer** instance at the specified offset.
......@@ -2221,8 +2221,8 @@ Writes an unsigned, little-endian 32-bit integer to this **Buffer** instance at
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| value | number | Yes| Number to write.|
| offset | number | No| Number of bytes to skip before writing data. The default value is **0**.|
| value | number | Yes| Data to write.|
| offset | number | No| Number of bytes to skip before starting to write data. The default value is **0**.|
**Return value**
......@@ -2242,9 +2242,9 @@ buf.writeUInt32LE(0xfeedface, 0);
### writeUIntBE
writeUIntBE(value : number, offset : number, byteLength : number): number
writeUIntBE(value: number, offset: number, byteLength: number): number
Writes a big-endian unsigned value of the specified length to this **Buffer** instance at the specified offset.
Writes an unsigned big-endian value of the specified length to this **Buffer** instance at the specified offset.
**System capability**: SystemCapability.Utils.Lang
......@@ -2253,8 +2253,8 @@ Writes a big-endian unsigned value of the specified length to this **Buffer** in
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| value | number | Yes| Data to write.|
| offset | number | No| Number of bytes to skip before writing data. The default value is **0**.|
| byteLength | number | No| Number of bytes to write.|
| offset | number | Yes| Number of bytes to skip before starting to write data. The default value is **0**.|
| byteLength | number | Yes| Number of bytes to write.|
**Return value**
......@@ -2274,9 +2274,9 @@ buf.writeUIntBE(0x1234567890ab, 0, 6);
### writeUIntLE
writeUIntLE(value : number, offset : number, byteLength : number): number
writeUIntLE(value: number, offset: number, byteLength: number): number
Writes a little-endian unsigned value of the specified length to this **Buffer** instance at the specified offset.
Writes an unsigned little-endian value of the specified length to this **Buffer** instance at the specified offset.
**System capability**: SystemCapability.Utils.Lang
......@@ -2285,8 +2285,8 @@ Writes a little-endian unsigned value of the specified length to this **Buffer**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| value | number | Yes| Data to write.|
| offset | number | No| Number of bytes to skip before writing data. The default value is **0**.|
| byteLength | number | No| Number of bytes to write.|
| offset | number | Yes| Number of bytes to skip before starting to write data. The default value is **0**.|
| byteLength | number | Yes| Number of bytes to write.|
**Return value**
......@@ -2306,7 +2306,7 @@ buf.writeUIntLE(0x1234567890ab, 0, 6);
### transcode
transcode(source : Buffer | Uint8Array, fromEnc : string, toEnc : string): Buffer
transcode(source: Buffer | Uint8Array, fromEnc: string, toEnc: string): Buffer
Transcodes the given **Buffer** or **Uint8Array** instance from one encoding format to another.
......@@ -2316,7 +2316,7 @@ Transcodes the given **Buffer** or **Uint8Array** instance from one encoding for
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| source | Buffer&nbsp;\|&nbsp;Uint8Array | Yes| Instance to encode.|
| source | Buffer&nbsp;\|&nbsp;Uint8Array | Yes| Instance to transcode. |
| fromEnc | string | Yes| Current encoding format.|
| toEnc | string | Yes| Target encoding format.|
......@@ -2332,7 +2332,7 @@ Transcodes the given **Buffer** or **Uint8Array** instance from one encoding for
import buffer from '@ohos.buffer';
let buf = buffer.alloc(50);
let newBuf = buf.transcode(buffer.from('€'), 'utf8', 'ascii');
let newBuf = buffer.transcode(buffer.from('€'), 'utf-8', 'ascii');
console.log(newBuf.toString('ascii'));
```
......@@ -2349,7 +2349,7 @@ console.log(newBuf.toString('ascii'));
### constructor
constructor(sources: string[] | ArrayBuffer[] | TypedArray[] | DataView[] | Blob[] , options: Object)
constructor(sources: string[] | ArrayBuffer[] | TypedArray[] | DataView[] | Blob[] , options?: Object)
A constructor used to create a **Blob** instance.
......@@ -2368,7 +2368,7 @@ A constructor used to create a **Blob** instance.
```ts
import buffer from '@ohos.buffer';
let blob1 = new buffer.Blob(['a', 'b', 'c']);
let blob = new buffer.Blob(['a', 'b', 'c']);
let blob1 = new buffer.Blob(['a', 'b', 'c'], {endings:'native', type: 'MIME'});
```
......@@ -2390,7 +2390,8 @@ Puts the **Blob** data into an **ArrayBuffer** instance. This API uses a promise
let blob = new buffer.Blob(['a', 'b', 'c']);
let pro = blob.arrayBuffer();
pro.then(val => {
console.log(val)
let uintarr = new Uint8Array(val);
console.log(uintarr.toString());
});
```
### slice
......@@ -2412,7 +2413,7 @@ Creates a **Blob** instance by copying specified data from this **Blob** instanc
**Return value**
| Type| Description|
| -------- | -------- |
| Blob | New **Blob** instance created.|
| Blob | **Blob** instance created. |
**Example**
```ts
......
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