# zlib

The **zlib** module provides APIs for file compression and decompression.

> **NOTE**
>
> The initial APIs of this module are supported since API version 7. Newly added APIs will be marked with a superscript to indicate their earliest API version.

## Modules to Import

```javascript
import zlib from '@ohos.zlib';
```

## zlib.zipFile<sup>(deprecated)</sup>
zipFile(inFile: string, outFile: string, options: Options): Promise&lt;void&gt;

Zips a file. This API uses a promise to return the result.

> This API is deprecated since API version 9. You are advised to use [zlib.compressFile](#zlibcompressfile9) instead.

**System capability**: SystemCapability.BundleManager.Zlib

**Parameters**

| Name | Type               | Mandatory| Description                                                        |
| ------- | ------------------- | ---- | ------------------------------------------------------------ |
| inFile  | string              | Yes  | Path of the folder or file to zip. For details about the path, see [FA Model](js-apis-Context.md) or [Stage Model](js-apis-application-context.md).|
| outFile | string              | Yes  | Path of the zipped file. The file name extension is .zip.                   |
| options | [Options](#options) | No  | Optional parameters for the zip operation.                                              |

**Return value**

| Type          | Description                                                        |
| -------------- | ------------------------------------------------------------ |
| Promise\<void> | Returns [ERROR_CODE_OK](#ziperrorcode) if the operation is successful.<br>Returns [ERROR_CODE_ERRNO](#ziperrorcode) if the operation fails.|

**Example 1**

```typescript
// Zip a file.
import zlib from '@ohos.zlib';
let inFile = '/xxx/filename.xxx';
let outFile = '/xxx/xxx.zip';
let options = {
  level: zlib.CompressLevel.COMPRESS_LEVEL_DEFAULT_COMPRESSION,
  memLevel: zlib.MemLevel.MEM_LEVEL_DEFAULT,
  strategy: zlib.CompressStrategy.COMPRESS_STRATEGY_DEFAULT_STRATEGY
};

zlib.zipFile(inFile, outFile, options).then((data) => {
    console.log('zipFile result is ' + JSON.Stringify(data));
}).catch((err) => {
    console.log('error is ' + JSON.Stringify(err));
});
```

**Example 2**

```typescript
// Zip a folder.
import zlib from '@ohos.zlib';
let inFile = '/xxx/xxx';
let outFile = '/xxx/xxx.zip';
let options = {
  level: zlib.CompressLevel.COMPRESS_LEVEL_DEFAULT_COMPRESSION,
  memLevel: zlib.MemLevel.MEM_LEVEL_DEFAULT,
  strategy: zlib.CompressStrategy.COMPRESS_STRATEGY_DEFAULT_STRATEGY
};

zlib.zipFile(inFile , outFile, options).then((data) => {
    console.log('zipFile result is ' + JSON.Stringify(data));
}).catch((err)=>{
    console.log('error is ' + JSON.Stringify(err));
});
```

## zlib.unzipFile<sup>(deprecated)</sup>

unzipFile(inFile:string, outFile:string, options: Options): Promise&lt;void&gt;

Unzips a file. This API uses a promise to return the result.

> This API is deprecated since API version 9. You are advised to use [zlib.decompressFile](#zlibdecompressfile9) instead.

**System capability**: SystemCapability.BundleManager.Zlib

**Parameters**

| Name | Type               | Mandatory| Description                                                        |
| ------- | ------------------- | ---- | ------------------------------------------------------------ |
| inFile  | string              | Yes  | Path of the folder or file to unzip. For details about the path, see [FA Model](js-apis-Context.md) or [Stage Model](js-apis-application-context.md).|
| outFile | string              | Yes  | Path of the unzipped file.                                          |
| options | [Options](#options) | No  | Optional parameters for the unzip operation.                                              |

**Return value**

| Type          | Description                                                        |
| -------------- | ------------------------------------------------------------ |
| Promise\<void> | Returns [ERROR_CODE_OK](#ziperrorcode) if the operation is successful.<br>Returns [ERROR_CODE_ERRNO](#ziperrorcode) if the operation fails.|

**Example**

```typescript
// Unzip a file.
import zlib from '@ohos.zlib';
let inFile = '/xx/xxx.zip';
let outFile = '/xxx';

let options = {
  level: zlib.CompressLevel.COMPRESS_LEVEL_DEFAULT_COMPRESSION,
  memLevel: zlib.MemLevel.MEM_LEVEL_DEFAULT,
  strategy: zlib.CompressStrategy.COMPRESS_STRATEGY_DEFAULT_STRATEGY
};
zlib.unzipFile(inFile, outFile, options).then((data) => {
    console.log('unzipFile result is ' + JSON.Stringify(data));
}).catch((err)=>{
    console.log('error is ' + JSON.Stringify(err));
})
```

## zlib.compressFile<sup>9+</sup>

compressFile(inFile: string, outFile: string, options: Options, callback: AsyncCallback\<void>): void;

Compresses a file. This API uses an asynchronous callback to return the result.  

**System capability**: SystemCapability.BundleManager.Zlib

**Parameters**

| Name                 | Type               | Mandatory| Description                                                        |
| ----------------------- | ------------------- | ---- | ------------------------------------------------------------ |
| inFile                  | string              | Yes  | Path of the folder or file to compress. For details about the path, see [FA Model](js-apis-Context.md) or [Stage Model](js-apis-application-context.md).|
| outFile                 | string              | Yes  | Path of the compressed file.                                          |
| options                 | [Options](#options) | Yes  | Compression parameters.                                              |
| AsyncCallback<**void**> | callback            | No  | Callback used to return the result. If the operation is successful, **null** is returned; otherwise, a specific error code is returned.                                            |

**Error codes**

| ID| Error Message                              |
| ------ | -------------------------------------- |
| 401    | wrong param type                       |
| 900001 | The Input source file is invalid.      |
| 900002 | The Input destination file is invalid. |

**Example**

```typescript
// Compress a file.
// The path used in the code must be the application sandbox path, for example, /data/storage/el2/base/haps. You can obtain the path through context.
import zlib from '@ohos.zlib';
let inFile = '/xxx/filename.xxx';
let outFile = '/xxx/xxx.zip';
let options = {
  level: zlib.CompressLevel.COMPRESS_LEVEL_DEFAULT_COMPRESSION,
  memLevel: zlib.MemLevel.MEM_LEVEL_DEFAULT,
  strategy: zlib.CompressStrategy.COMPRESS_STRATEGY_DEFAULT_STRATEGY
};

try {
    zlib.compressFile(inFile, outFile, options, (errData) => {
        if (erData !== null) {
            console.log(`errData is errCode:${errData.errCode}  message:${errData.message}`);
        }
    })
} catch(errData) {
    console.log(`errData is errCode:${errData.errCode}  message:${errData.message}`);
}
```

compressFile(inFile: string, outFile: string, options: Options): Promise\<void>;

Compresses a file. This API uses a promise to return the result.

**System capability**: SystemCapability.BundleManager.Zlib

**Parameters**

| Name | Type               | Mandatory| Description                                                        |
| ------- | ------------------- | ---- | ------------------------------------------------------------ |
| inFile  | string              | Yes  | Path of the folder or file to compress. For details about the path, see [FA Model](js-apis-Context.md) or [Stage Model](js-apis-application-context.md).|
| outFile | string              | Yes  | Path of the compressed file.                                          |
| options | [Options](#options) | Yes  | Compression parameters.                                              |

**Error codes**

| ID| Error Message                              |
| ------ | -------------------------------------- |
| 401    | wrong param type                       |
| 900001 | The Input source file is invalid.      |
| 900002 | The Input destination file is invalid. |

```typescript
// Compress a file.
// The path used in the code must be the application sandbox path, for example, /data/storage/el2/base/haps. You can obtain the path through context.
import zlib from '@ohos.zlib';
let inFile = '/xxx/filename.xxx';
let outFile = '/xxx/xxx.zip';
let options = {
  level: zlib.CompressLevel.COMPRESS_LEVEL_DEFAULT_COMPRESSION,
  memLevel: zlib.MemLevel.MEM_LEVEL_DEFAULT,
  strategy: zlib.CompressStrategy.COMPRESS_STRATEGY_DEFAULT_STRATEGY
};

try {
    zlib.compressFile(inFile, outFile, options).then((data) => {
        console.info('compressFile success');
    }).catch((errData) => {
        console.log(`errData is errCode:${errData.errCode}  message:${errData.message}`);
    })
} catch(errData) {
    console.log(`errData is errCode:${errData.errCode}  message:${errData.message}`);
}
```



## zlib.decompressFile<sup>9+</sup>

decompressFile(inFile: string, outFile: string, options: Options, callback: AsyncCallback\<void>): void;

Decompresses a file. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.BundleManager.Zlib

**Parameters**

| Name                 | Type               | Mandatory| Description                                                        |
| ----------------------- | ------------------- | ---- | ------------------------------------------------------------ |
| inFile                  | string              | Yes  | Path of the file to decompress. For details about the path, see [FA Model](js-apis-Context.md) or [Stage Model](js-apis-application-context.md).|
| outFile                 | string              | Yes  | Path of the decompressed file.                                      |
| options                 | [Options](#options) | Yes  | Decompression parameters.                                              |
| AsyncCallback<**void**> | callback            | No  | Callback used to return the result. If the operation is successful, **null** is returned; otherwise, a specific error code is returned.                                            |

**Error codes**

| ID| Error Message                              |
| ------ | -------------------------------------- |
| 401    | wrong param type                       |
| 900001 | The Input source file is invalid.      |
| 900002 | The Input destination file is invalid. |

**Example**

```typescript
// Decompress a file.
// The path used in the code must be the application sandbox path, for example, /data/storage/el2/base/haps. You can obtain the path through context.
import zlib from '@ohos.zlib';
let inFile = '/xx/xxx.zip';
let outFile = '/xxx';
let options = {
  level: zlib.CompressLevel.COMPRESS_LEVEL_DEFAULT_COMPRESSION,
  memLevel: zlib.MemLevel.MEM_LEVEL_DEFAULT,
  strategy: zlib.CompressStrategy.COMPRESS_STRATEGY_DEFAULT_STRATEGY
};

try {
    zlib.decompressFile(inFile, outFile, options, (errData) => {
        if (erData !== null) {
            console.log(`errData is errCode:${errData.errCode}  message:${errData.message}`);
        }
    })
} catch(errData) {
    console.log(`errData is errCode:${errData.errCode}  message:${errData.message}`);
}
```

decompressFile(inFile: string, outFile: string, options: Options): Promise\<void>;

Decompress a file. This API uses a promise to return the result.

**System capability**: SystemCapability.BundleManager.Zlib

**Parameters**

| Name | Type               | Mandatory| Description                                                        |
| ------- | ------------------- | ---- | ------------------------------------------------------------ |
| inFile  | string              | Yes  | Path of the file to decompress. For details about the path, see [FA Model](js-apis-Context.md) or [Stage Model](js-apis-application-context.md).|
| outFile | string              | Yes  | Path of the decompressed file.                                      |
| options | [Options](#options) | Yes  | Decompression parameters.                                            |

**Error codes**

| ID| Error Message                              |
| ------ | -------------------------------------- |
| 401    | wrong param type                       |
| 900001 | The Input source file is invalid.      |
| 900002 | The Input destination file is invalid. |

```typescript
// Decompress a file.
// The path used in the code must be the application sandbox path, for example, /data/storage/el2/base/haps. You can obtain the path through context.
import zlib from '@ohos.zlib';
let inFile = '/xx/xxx.zip';
let outFile = '/xxx';
let options = {
  level: zlib.CompressLevel.COMPRESS_LEVEL_DEFAULT_COMPRESSION,
  memLevel: zlib.MemLevel.MEM_LEVEL_DEFAULT,
  strategy: zlib.CompressStrategy.COMPRESS_STRATEGY_DEFAULT_STRATEGY
};

try {
    zlib.deCompressFile(inFile, outFile, options).then((data) => {
        console.info('deCompressFile success');
    }).catch((errData) => {
        console.log(`errData is errCode:${errData.errCode}  message:${errData.message}`);
    })
} catch(errData) {
    console.log(`errData is errCode:${errData.errCode}  message:${errData.message}`);
}
```

## Options

**System capability**: SystemCapability.BundleManager.Zlib

| Name  | Type            | Mandatory| Description                                                     |
| -------- | ---------------- | ---- | --------------------------------------------------------- |
| level    | CompressLeve     | No  | See [zip.CompressLevel](#zipcompresslevel).      |
| memLevel | MemLevel         | No  | See [zip.MemLevel](#zipmemlevel).                |
| strategy | CompressStrategy | No  | See [zip.CompressStrategy](#zipcompressstrategy).|

## zip.CompressLevel

**System capability**: SystemCapability.BundleManager.Zlib

| Name                              | Value  | Description             |
| ---------------------------------- | ---- | ----------------- |
| COMPRESS_LEVEL_NO_COMPRESSION      | 0    | Compress level 0 that indicates uncompressed.|
| COMPRESS_LEVEL_BEST_SPEED          | 1    | Compression level 1 that gives the best speed. |
| COMPRESS_LEVEL_BEST_COMPRESSION    | 9    | Compression level 9 that gives the best compression.     |
| COMPRESS_LEVEL_DEFAULT_COMPRESSION | -1   | Default compression level.     |

## zip.MemLevel

**System capability**: SystemCapability.BundleManager.Zlib

| Name             | Value  | Description                            |
| ----------------- | ---- | -------------------------------- |
| MEM_LEVEL_MIN     | 1    | Minimum memory used by the **zip** API during compression.|
| MEM_LEVEL_MAX     | 9    | Maximum memory used by the **zip** API during compression.|
| MEM_LEVEL_DEFAULT | 8    | Default memory used by the **zip** API during compression.|

## zip.CompressStrategy

**System capability**: SystemCapability.BundleManager.Zlib

| Name                              | Value  | Description                    |
| ---------------------------------- | ---- | ------------------------ |
| COMPRESS_STRATEGY_DEFAULT_STRATEGY | 0    | Default compression strategy.            |
| COMPRESS_STRATEGY_FILTERED         | 1    | Filtered compression strategy.|
| COMPRESS_STRATEGY_HUFFMAN_ONLY     | 2    | Huffman coding compression strategy.  |
| COMPRESS_STRATEGY_RLE              | 3    | RLE compression strategy.        |
| COMPRESS_STRATEGY_FIXED            | 4    | Fixed compression strategy.          |

## zip.ErrorCode

**System capability**: SystemCapability.BundleManager.Zlib

| Name            | Value  | Description        |
| ---------------- | ---- | ------------ |
| ERROR_CODE_OK    | 0    | The API is successfully called.|
| ERROR_CODE_ERRNO | -1   | Failed to call the API.|