# util >**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. This module provides common utility functions, such as **TextEncoder** and **TextDecoder** for string encoding and decoding, **RationalNumber** for rational number operations, **LruBuffer** for buffer management, **Scope** for range determination, **Base64** for Base64 encoding and decoding, and **Types** for checks of built-in object types. ## Modules to Import ``` import util from '@ohos.util'; ``` ## Required Permissions None. ## util.printf printf\(format: string, ...args: Object\[\]\): string Prints the input content in a formatted string. - Parameters

Name	Type	Mandatory	Description
format	string	Yes	Format of the string to print.
...args	Object[]	No	Data to format.

- Return values

Type	Description
string	String in the specified format.

- Example ``` var res = util.printf("%s", "hello world!"); console.log(res); ``` ## util.getErrorString getErrorString\(errno: number\): string Obtains detailed information about a system error code. - Parameters

Name	Type	Mandatory	Description
errno	number	Yes	Error code generated.

- Return values

Type	Description
string	Detailed information about the error code.

- Example ``` var errnum = 10; // 10 is the system error code. var result = util.getErrorString(errnum); console.log("result = " + result); ``` ## util.callbackWrapper callbackWrapper\(original: Function\): \(err: Object, value: Object \)=\>void Calls back an asynchronous function. In the callback, the first parameter indicates the cause of the rejection \(the value is **null** if the promise has been resolved\), and the second parameter indicates the resolved value. - Parameters

Name	Type	Mandatory	Description
original	Function	Yes	Asynchronous function to process.

- Return values

Type	Description
Function	Callback, in which the first parameter indicates the cause of the rejection (the value is null if the promise has been resolved) and the second parameter indicates the resolved value.

- Example ``` async function promiseFn() { return Promise.reject('value'); } var cb = util.callbackWrapper(promiseFn); cb((err, ret) => { console.log(err); console.log(ret); }) ``` ## util.promiseWrapper promiseWrapper\(original: \(err: Object, value: Object\) =\> void\): Object Processes an asynchronous function and returns a promise version. - Parameters

Name	Type	Mandatory	Description
original	Function	Yes	Asynchronous function to process.

- Return values

Type	Description
Function	Function in the error-first style (that is, (err, value) =>... is called as the last parameter) and the promise version.

- Example ``` function aysnFun(str1, str2, callback) { if (typeof str1 === 'string' && typeof str1 === 'string') { callback(null, str1 + str2); } else { callback('type err'); } } let newPromiseObj = util.promiseWrapper(aysnFun)("Hello", 'World'); newPromiseObj.then(res => { console.log(res); }) ``` ## TextDecoder ### Attributes

Name	Type	Readable	Writable	Description
encoding	string	Yes	No	Encoding format. Supported formats: utf-8, ibm866, iso-8859-2, iso-8859-3, iso-8859-4, iso-8859-5, iso-8859-6, iso-8859-7, iso-8859-8, iso-8859-8-i, iso-8859-10, iso-8859-13, iso-8859-14, iso-8859-15, koi8-r, koi8-u, macintosh, windows-874, windows-1250, windows-1251, windows-1252, windows-1253, windows-1254, windows-1255, windows-1256, windows-1257, windows-1258, x-mac-cyrilli, gbk, gb18030, big5, euc-jp, iso-2022-jp, shift_jis, euc-kr, utf-16be, utf-16le
fatal	boolean	Yes	No	Whether to display fatal errors.
ignoreBOM	boolean	Yes	No	Whether to ignore the byte order marker (BOM). The default value is false, which indicates that the result contains the BOM.

Name

Type

Readable

Writable

Description

encoding

string

Yes

Encoding format.

Supported formats: utf-8, ibm866, iso-8859-2, iso-8859-3, iso-8859-4, iso-8859-5, iso-8859-6, iso-8859-7, iso-8859-8, iso-8859-8-i, iso-8859-10, iso-8859-13, iso-8859-14, iso-8859-15, koi8-r, koi8-u, macintosh, windows-874, windows-1250, windows-1251, windows-1252, windows-1253, windows-1254, windows-1255, windows-1256, windows-1257, windows-1258, x-mac-cyrilli, gbk, gb18030, big5, euc-jp, iso-2022-jp, shift_jis, euc-kr, utf-16be, utf-16le

fatal

boolean

Yes

Whether to display fatal errors.

ignoreBOM

boolean

Yes

Whether to ignore the byte order marker (BOM). The default value is false, which indicates that the result contains the BOM.

### constructor constructor\(encoding?:string, options?:\{ fatal?:boolean;ignoreBOM?:boolean \}\) A constructor used to create a **TextDecoder** object. - Parameters

Name	Type	Mandatory	Description
encoding	string	No	Encoding format.
options	Object	No	Encoding-related options, which include fatal and ignoreBOM.

**Table 1** options

Name	Type	Mandatory	Description
fatal	boolean	No	Whether to display fatal errors.
ignoreBOM	boolean	No	Whether to ignore the BOM.

- Example ``` var textDecoder = new util.TextDecoder("utf-8",{ignoreBOM:true}); ``` ### decode decode\(input: Unit8Array, options?:\{stream?:false\}\):string Decodes the input content. - Parameters

Name	Type	Mandatory	Description
input	Unit8Array	Yes	Uint8Array to decode.
options	Object	No	Options related to decoding.

**Table 2** options

Name	Type	Mandatory	Description
stream	boolean	No	Whether to allow data blocks in subsequent decode(). If data is processed in blocks, set this parameter to true. If this is the last data block to process or data is not divided into blocks, set this parameter to false. The default value is false.

- Return values

Type	Description
string	Data decoded.

- Example ``` var textDecoder = new util.TextDecoder("utf-8",{ignoreBOM:true}); var result = new Uint8Array(6); result[0] = 0xEF; result[1] = 0xBB; result[2] = 0xBF; result[3] = 0x61; result[4] = 0x62; result[5] = 0x63; console.log("input num:"); for(var j= 0; j < 6; j++) { console.log(result[j]); } var retStr = textDecoder.decode( result , {stream:false}); console.log("retStr = " + retStr); ``` ## TextEncoder ### Attributes

Name	Type	Readable	Writable	Description
encoding	string	Yes	No	Encoding format. The default format is utf-8.

### constructor constructor\(\) A constructor used to create a **TextEncoder** object. - Example ``` var textEncoder = new util.TextEncoder(); ``` ### encode encode\(input?:string\):Uint8Array Encodes the input content. - Parameters

Name	Type	Mandatory	Description
input	string	Yes	String to encode.

- Return values

Type	Description
Uint8Array	Encoded text.

- Example ``` var textEncoder = new util.TextEncoder(); var result = new Uint8Array(buffer); result = textEncoder.encode("\uD800¥¥"); ``` ### encodeInto encodeInto\(input:string, dest:Uint8Array, \):\{ read:number; written:number \} Stores the UTF-8 encoded text. - Parameters

Name	Type	Mandatory	Description
input	string	Yes	String to encode.
dest	Uint8Array	Yes	Uint8Array object used to hold the UTF-8 encoded text.

- Return values

Type	Description
Uint8Array	Encoded text.

- Example ``` var that = new util.TextEncoder(); var buffer = new ArrayBuffer(4); this.dest = new Uint8Array(buffer); var result = that.encodeInto("abcd", this.dest); ``` ## RationalNumber⁸⁺ ### constructor⁸⁺ constructor\(numerator:number,denominator:number\) A constructor used to create a **RationalNumber** object. - Parameters

Name	Type	Mandatory	Description
numerator	number	Yes	Numerator, which is an integer.
denominator	number	Yes	Denominator, which is an integer.

- Example ``` var rationalNumber = new util.RationalNumber(1,2); ``` ### createRationalFromString⁸⁺ static createRationalFromString\(rationalString:string\):RationalNumber Creates a **RationalNumber** object using the given string. - Parameters

Name	Type	Mandatory	Description
rationalString	string	Yes	String used to create the RationalNumber object.

- Return values

Type	Description
object	RationalNumber object created.

- Example ``` var rationalNumber = new util.RationalNumber(1,2); var rational = rationalNumer.creatRationalFromString("3/4"); ``` ### compareTo⁸⁺ compareTo\(another:RationalNumber\):number Compares this **RationalNumber** object with a given object. - Parameters

Name	Type	Mandatory	Description
another	RationalNumber	Yes	Object used to compare with this RationalNumber object.

- Return values

Type	Description
number	Returns 0 if the two objects are equal; returns 1 if the given object is less than this object; return -1 if the given object is greater than this object.

- Example ``` var rationalNumber = new util.RationalNumber(1,2); var rational = rationalNumer.creatRationalFromString("3/4"); var result = rationalNumber.compareTo(rational); ``` ### valueOf⁸⁺ valueOf\(\):number Obtains the value of this **RationalNumber** object as an integer or a floating-point number. - Return values

Type	Description
number	An integer or a floating-point number.

- Example ``` var rationalNumber = new util.RationalNumber(1,2); var result = rationalNumber.valueOf(); ``` ### equals⁸⁺ equals\(obj:Object\):boolean Checks whether this **RationalNumber** object equals the given object. - Parameters

Name	Type	Mandatory	Description
object	Object	Yes	Object used to compare with this RationalNumber object.

- Return values

Type	Description
boolean	Returns true if the two objects are equal; returns false otherwise.

- Example ``` var rationalNumber = new util.RationalNumber(1,2); var rational = rationalNumer.creatRationalFromString("3/4"); var result = rationalNumber.equals(rational); ``` ### getCommonDivisor⁸⁺ static getCommonDivisor\(number1:number,number2:number\):number Obtains the greatest common divisor of the two specified integers. - Parameters

Name	Type	Mandatory	Description
number1	number	Yes	The first integer used to get the greatest common divisor.
number2	number	Yes	The second integer used to get the greatest common divisor.

- Return values

Type	Description
number	Greatest common divisor obtained.

- Example ``` var rationalNumber = new util.RationalNumber(1,2); var result = rationalNumber.getCommonDivisor(4,6); ``` ### getNumerator⁸⁺ getNumerator\(\):number Obtains the numerator of this **RationalNumber** object. - Return values

Type	Description
number	Numerator of this RationalNumber object.

- Example ``` var rationalNumber = new util.RationalNumber(1,2); var result = rationalNumber.getNumerator(); ``` ### getDenominator⁸⁺ getDenominator\(\):number Obtains the denominator of this **RationalNumber** object. - Return values

Type	Description
number	Denominator of this RationalNumber object.

- Example ``` var rationalNumber = new util.RationalNumber(1,2); var result = rationalNumber.getDenominator(); ``` ### isZero⁸⁺ isZero\(\):boolean Checks whether this **RationalNumber** object is **0**. - Return values

Type	Description
boolean	Returns true if the value of this RationalNumber object is 0; returns false otherwise.

- Example ``` var rationalNumber = new util.RationalNumber(1,2); var result = rationalNumber.isZero(); ``` ### isNaN⁸⁺ isNaN\(\):boolean Checks whether this **RationalNumber** object is a Not a Number \(NaN\). - Return values

Type	Description
boolean	Returns true if this RationalNumber object is a NaN (the denominator and numerator are both 0); returns false otherwise.

- Example ``` var rationalNumber = new util.RationalNumber(1,2); var result = rationalNumber.isNaN(); ``` ### isFinite⁸⁺ isFinite\(\):boolean Checks whether this **RationalNumber** object represents a finite value. - Return values

Type	Description
boolean	Returns true if this RationalNumber object represents a finite value (the denominator is not 0); returns false otherwise.

- Example ``` var rationalNumber = new util.RationalNumber(1,2); var result = rationalNumber.isFinite(); ``` ### toString⁸⁺ toString\(\):string Obtains the string representation of this **RationalNumber** object. - Return values

Type	Description
string	Returns NaN if the numerator and denominator of this object are both 0; returns a string in Numerator/Denominator format otherwise, for example, 3/5.

- Example ``` var rationalNumber = new util.RationalNumber(1,2); var result = rationalNumber.toString(); ``` ## LruBuffer⁸⁺ ### Attributes

Name	Type	Readable	Writable	Description
length	number	Yes	No	Total number of values in this buffer.

- Example ``` var pro = new util.LruBuffer(); pro.put(2,10); pro.put(1,8); var result = pro.length; ``` ### constructor⁸⁺ constructor\(capacity?:number\) A constructor used to create an **LruBuffer** instance. The default capacity of the buffer is 64. - Parameters

Name	Type	Mandatory	Description
capacity	number	No	Capacity of the LruBuffer to create.

- Example ``` var lrubuffer= new util.LruBuffer(); ``` ### updateCapacity⁸⁺ updateCapacity\(newCapacity:number\):void Changes the **LruBuffer** capacity. If the new capacity is less than or equal to **0**, an exception will be thrown. - Parameters

Name	Type	Mandatory	Description
newCapacity	number	Yes	New capacity of the buffer.

- Example ``` var pro = new util.LruBuffer(); var result = pro.updateCapacity(100); ``` ### toString⁸⁺ toString\(\):string Obtains the string representation of this **LruBuffer** object. - Return values

Type	Description
string	String representation of this object.

- Example ``` var pro = new util.LruBuffer(); pro.put(2,10); pro.get(2); pro.remove(20); var result = pro.toString(); ``` ### getCapacity⁸⁺ getCapacity\(\):number Obtains the capacity of this buffer. - Return values

Type	Description
number	Capacity of this buffer.

- Example ``` var pro = new util.LruBuffer(); var result = pro.getCapacity(); ``` ### clear⁸⁺ clear\(\):void Clears key-value pairs from this buffer. The **afterRemoval\(\)** method will be called to perform subsequent operations. - Example ``` var pro = new util.LruBuffer(); pro.put(2,10); var result = pro.size(); pro.clear(); ``` ### getCreateCount⁸⁺ getCreateCount\(\):number Obtains the number of return values for **createDefault\(\)**. - Return values

Type	Description
number	Number of return values for createDefault().

- Example ``` var pro = new util.LruBuffer(); pro.put(1,8); var result = pro.getCreateCount(); ``` ### getMissCount⁸⁺ getMissCount\(\):number Obtains the number of times that the queried values are mismatched. - Return values

Type	Description
number	Number of times that the queried values are mismatched.

- Example ``` var pro = new util.LruBuffer(); pro.put(2,10); pro.get(2) var result = pro.getMissCount(); ``` ### getRemovalCount⁸⁺ getRemovalCount\(\):number Obtains the number of removals from this buffer. - Return values

Type	Description
number	Number of removals from the buffer.

- Example ``` var pro = new util.LruBuffer(); pro.put(2,10); pro.updateCapacity(2); pro.put(50,22); var result = pro.getRemovalCount(); ``` ### getMatchCount⁸⁺ getMatchCount\(\):number Obtains the number of times that the queried values are matched. - Return values

Type	Description
number	Number of times that the queried values are matched.

- Example ``` var pro = new util.LruBuffer(); pro.put(2,10); pro.get(2); var result = pro.getMatchCount(); ``` ### getPutCount⁸⁺ getPutCount\(\):number Obtains the number of additions to this buffer. - Return values

Type	Description
number	Number of additions to the buffer.

- Example ``` var pro = new util.LruBuffer(); pro.put(2,10); var result = pro.getPutCount(); ``` ### isEmpty⁸⁺ isEmpty\(\):boolean Checks whether this buffer is empty. - Return values

Type	Description
boolean	Returns true if the buffer does not contain any value.

- Example ``` var pro = new util.LruBuffer(); pro.put(2,10); var result = pro.isEmpty(); ``` ### get⁸⁺ get\(key:K\):V | undefined Obtains the value of the specified key. - Parameters

Name	Type	Mandatory	Description
key	K	Yes	Key based on which the value is queried.

- Return values

Type	Description
V \| undefind	Returns the value of the key if a match is found in the buffer; returns undefined otherwise.

- Example ``` var pro = new util.LruBuffer(); pro.put(2,10); var result = pro.get(2); ``` ### put⁸⁺ put\(key:K,value:V\):V Adds a key-value pair to this buffer. - Parameters

Name	Type	Mandatory	Description
key	K	Yes	Key of the key-value pair to add.
value	V	Yes	Value of the key-value pair to add.

- Return values

Type	Description
V	Returns the existing value if the key already exists; returns the value added otherwise. If the key or value is null, an exception will be thrown.

- Example ``` var pro = new util.LruBuffer(); var result = pro.put(2,10); ``` ### values⁸⁺ values\(\):V\[\] Obtains all values in this buffer, listed from the most to the least recently accessed. - Return values

Type	Description
V []	All values in the buffer, listed from the most to the least recently accessed.

- Example ``` var pro = new util.LruBuffer(); pro.put(2,10); pro.put(2,"anhu"); pro.put("afaf","grfb"); var result = pro.values(); ``` ### keys⁸⁺ keys\(\):K\[\] Obtains all keys in this buffer, listed from the most to the least recently accessed. - Return values

Type	Description
K []	All keys in the buffer, listed from the most to the least recently accessed.

- Example ``` var pro = new util.LruBuffer(); pro.put(2,10); var result = pro.keys(); ``` ### remove⁸⁺ remove\(key:K\):V | undefined Deletes the specified key and its value from this buffer. - Parameters

Name	Type	Mandatory	Description
key	K	Yes	Key to delete.

- Return values

Type	Description
V \| undefind	Returns an Optional object containing the deleted key-value pair if the key exists in the buffer; returns an empty Optional object otherwise. If the key is null, an exception will be thrown.

- Example ``` var pro = new util.LruBuffer(); pro.put(2,10); var result = pro.remove(20); ``` ### afterRemoval⁸⁺ afterRemoval\(isEvict:boolean,key:K,value:V,newValue:V\):void Performs subsequent operations after a value is deleted. - Parameters

Name	Type	Mandatory	Description
isEvict	boolean	No	Whether the buffer capacity is insufficient. If the value is true, this method is called due to insufficient capacity.
key	K	Yes	Key deleted.
value	V	Yes	Value deleted.
newValue	V	No	New value for the key if the put() method is called and the key to be added already exists. In other cases, this parameter is left blank.

- Example ``` var arr = []; class ChildLruBuffer extends util.LruBuffer { constructor() { super(); } static getInstance() { if(this.instance == null) { this.instance = new ChildLruBuffer(); } return this.instance; } afterRemoval(isEvict, key, value, newValue) { if (isEvict === false) { arr = [key, value, newValue]; } } } ChildLruBuffer.getInstance().afterRemoval(false,10,30,null); ``` ### contains⁸⁺ contains\(key:K\):boolean Checks whether this buffer contains the specified key. - Parameters

Name	Type	Mandatory	Description
key	K	Yes	Key to check.

- Return values

Type	Description
boolean	Returns true if the buffer contains the specified key; returns false otherwise.

- Example ``` var pro = new util.LruBuffer(); pro.put(2,10); var result = pro.contains(20); ``` ### createDefault⁸⁺ createDefault\(key:K\):V Creates a value if the value of the specified key is not available. - Parameters

Name	Type	Mandatory	Description
key	K	Yes	Key of which the value is missing.

- Return values

Type	Description
V	Value of the key.

- Example ``` var pro = new util.LruBuffer(); var result = pro.createDefault(50); ``` ### entries⁸⁺ entries\(\):IterableIterator<\[K,V\]\> Obtains a new iterator object that contains all key-value pairs in this object. - Return values

Type	Description
[K, V]	Returns an iterable array.

- Example ``` var pro = new util.LruBuffer(); pro.put(2,10); var result = pro.entries(); ``` ### \[Symbol.iterator\]⁸⁺ \[Symbol.iterator\]\(\): IterableIterator<\[K, V\]\> Obtains a two-dimensional array in key-value pairs. - Return values

Type	Description
[K, V]	A two-dimensional array in key-value pairs.

- Example ``` var pro = new util.LruBuffer(); pro.put(2,10); var result = pro[symbol.iterator](); ``` ## Scope⁸⁺ ### ScopeType⁸⁺ Defines the type of values in a **Scope** object. The value type can be **ScopeComparable** or **number**. The values of the **ScopeComparable** type are used to implement the **compareTo** method. Therefore, ensure that the input parameters are comparable. ``` interface ScopeComparable{ compareTo(other:ScopeComparable):boolean; } type ScopeType = ScopeComparable | number; ``` Create a class to implement the **compareTo** method. In the subsequent sample code, **Temperature** is used as an example of the [ScopeType](#section876116244471) object. Example ``` class Temperature{ constructor(value){ this._temp = value; } comapreTo(value){ return this._temp >= value.getTemp(); } getTemp(){ return this._temp; } toString(){ return this._temp.toString(); } } ``` ### constructor⁸⁺ constructor\(lowerObj:ScopeType,upperObje:ScopeType\) A constructor used to create a **Scope** object with the specified upper and lower limits. - Parameters

Name	Type	Mandatory	Description
lowerObj	ScopeType	Yes	Lower limit of the Scope object.
upperObj	ScopeType	Yes	Upper limit of the Scope object.

- Example ``` var tempLower = new Temperature(30); var tempUpper = new Temperature(40); var range = new util.Scope(tempLower, tempUpper); ``` ### toString⁸⁺ toString\(\):string Obtains a string representation that contains this **Scope**. - Return values

Type	Description
string	String representation containing the Scope.

- Example ``` var tempLower = new Temperature(30); var tempUpper = new Temperature(40); var range = new util.Scope(tempLower, tempUpper); var result = range.toString(); ``` ### intersect⁸⁺ intersect\(range:Scope\):Scope Obtains the intersection of this **Scope** and the given **Scope**. - Parameters

Name	Type	Mandatory	Description
range	Scope	Yes	Scope specified.

- Return values

Type	Description
Scope	Intersection of this Scope and the given Scope.

- Example ``` var tempLower = new Temperature(30); var tempUpper = new Temperature(40); var range = new util.Scope(tempLower, tempUpper); var tempMiDF = new Temperature(35); var tempMidS = new Temperature(39); var rangeFir = new util.Scope(tempMiDF, tempMidS); range.intersect(rangeFir ); ``` ### intersect⁸⁺ intersect\(lowerObj:ScopeType,upperObj:ScopeType\):Scope Obtains the intersection of this **Scope** and the given lower and upper limits. - Parameters

Name	Type	Mandatory	Description
lowerObj	ScopeType	Yes	Lower limit.
upperObj	ScopeType	Yes	Upper limit.

- Return values

Type	Description
Scope	Intersection of this Scope and the given lower and upper limits.

- Example ``` var tempLower = new Temperature(30); var tempUpper = new Temperature(40); var tempMiDF = new Temperature(35); var tempMidS = new Temperature(39); var range = new util.Scope(tempLower, tempUpper); var result = range.intersect(tempMiDF, tempMidS); ``` ### getUpper⁸⁺ getUpper\(\):ScopeType Obtains the upper limit of this **Scope**. - Return values

Type	Description
ScopeType	Upper limit of this Scope.

- Example ``` var tempLower = new Temperature(30); var tempUpper = new Temperature(40); var range = new util.Scope(tempLower, tempUpper); var result = range.getUpper(); ``` ### getLower⁸⁺ getLower\(\):ScopeType Obtains the lower limit of this **Scope**. - Return values

Type	Description
ScopeType	Lower limit of this Scope.

- Example ``` var tempLower = new Temperature(30); var tempUpper = new Temperature(40); var range = new util.Scope(tempLower, tempUpper); var result = range.getLower(); ``` ### expand⁸⁺ expand\(lowerObj:ScopeType,upperObj:ScopeType\):Scope Obtains the union set of this **Scope** and the given lower and upper limits. - Parameters

Name	Type	Mandatory	Description
lowerObj	ScopeType	Yes	Lower limit.
upperObj	ScopeType	Yes	Upper limit.

- Return values

Type	Description
Scope	Union set of this Scope and the given lower and upper limits.

- Example ``` var tempLower = new Temperature(30); var tempUpper = new Temperature(40); var tempMiDF = new Temperature(35); var tempMidS = new Temperature(39); var range = new util.Scope(tempLower, tempUpper); var result = range.expand(tempMiDF, tempMidS); ``` ### expand⁸⁺ expand\(range:Scope\):Scope Obtains the union set of this **Scope** and the given **Scope**. - Parameters

Name	Type	Mandatory	Description
range	Scope	Yes	Scope specified.

- Return values

Type	Description
Scope	Union set of this Scope and the given Scope.

- Example ``` var tempLower = new Temperature(30); var tempUpper = new Temperature(40); var tempMiDF = new Temperature(35); var tempMidS = new Temperature(39); var range = new util.Scope(tempLower, tempUpper); var rangeFir = new util.Scope(tempMiDF, tempMidS); var result = range.expand(rangeFir); ``` ### expand⁸⁺ expand\(value:ScopeType\):Scope Obtains the union set of this **Scope** and the given value. - Parameters

Name	Type	Mandatory	Description
value	ScopeType	Yes	Value specified.

- Return values

Type	Description
Scope	Union set of this Scope and the given value.

- Example ``` var tempLower = new Temperature(30); var tempUpper = new Temperature(40); var tempMiDF = new Temperature(35); var range = new util.Scope(tempLower, tempUpper); var result = range.expand(tempMiDF); ``` ### contains⁸⁺ contains\(value:ScopeType\):boolean Checks whether a value is within this **Scope**. - Parameters

Name	Type	Mandatory	Description
value	ScopeType	Yes	Value specified.

- Return values

Type	Description
boolean	Returns true if the value is within this Scope; returns false otherwise.

- Example ``` var tempLower = new Temperature(30); var tempUpper = new Temperature(40); var tempMiDF = new Temperature(35); var range = new util.Scope(tempLower, tempUpper); range.contains(tempMiDF); ``` ### contains⁸⁺ contains\(range:Scope\):boolean Checks whether a range is within this **Scope**. - Parameters

Name	Type	Mandatory	Description
range	Scope	Yes	Range specified.

- Return values

Type	Description
boolean	Returns true if the range is within this Scope; returns false otherwise.

- Example ``` var tempLower = new Temperature(30); var tempUpper = new Temperature(40); var range = new util.Scope(tempLower, tempUpper); var tempLess = new Temperature(20); var tempMore = new Temperature(45); var rangeSec = new util.Scope(tempLess, tempMore); var result = range.contains(rangeSec); ``` ### clamp⁸⁺ clamp\(value:ScopeType\):ScopeType Limits a value to this **Scope**. - Parameters

Name	Type	Mandatory	Description
value	ScopeType	Yes	Value specified.

- Return values

Type	Description
ScopeType	Returns lowerObj if the specified value is less than the lower limit; returns upperObj if the specified value is greater than the upper limit; returns the specified value if it is within this Scope.

- Example ``` var tempLower = new Temperature(30); var tempUpper = new Temperature(40); var tempMiDF = new Temperature(35); var range = new util.Scope(tempLower, tempUpper); var result = range.clamp(tempMiDF); ``` ## Base64⁸⁺ ### constructor⁸⁺ constructor\(\) A constructor used to create a **Base64** object. - Example ``` var base64 = new util.Base64(); ``` ### encodeSync⁸⁺ encodeSync\(src:Uint8Array\):Uint8Array Encodes the input content. - Parameters

Name	Type	Mandatory	Description
src	Uint8Array	Yes	Uint8Array to encode.

- Return values

Type	Description
Uint8Array	Uint8Array encoded.

- Example ``` var that = new util.Base64(); var array = new Uint8Array([115,49,51]); var result = that.encodeSync(array); ``` ### encodeToStringSync⁸⁺ encodeToStringSync\(src:Uint8Array\):string Encodes the input content into a string. - Parameters

Name	Type	Mandatory	Description
src	Uint8Array	Yes	Uint8Array to encode.

- Return values

Type	Description
string	String encoded from the Uint8Array.

- Example ``` var that = new util.Base64(); var array = new Uint8Array([115,49,51]); var result = that.encodeToStringSync(array); ``` ### decodeSync⁸⁺ decodeSync\(src:Uint8Array | string\):Uint8Array Decodes the input content. - Parameters

Name	Type	Mandatory	Description
src	Uint8Array \| string	Yes	Uint8Array or string to decode.

- Return values

Type	Description
Uint8Array	Uint8Array decoded.

- Example ``` var that = new util.Base64(); var buff = 'czEz'; var result = that.decodeSync(buff); ``` ### encode⁸⁺ encode\(src:Uint8Array\):Promise Encodes the input content asynchronously. - Parameters

Name	Type	Mandatory	Description
src	Uint8Array	Yes	Uint8Array to encode asynchronously.

- Return values

Type	Description
Promise<Uint8Array>	Uint8Array obtained after asynchronous encoding.

- Example ``` var that = new util.Base64(); var array = new Uint8Array([115,49,51]); var rarray = new Uint8Array([99,122,69,122]); await that.encode(array).then(val=>{ for (var i = 0; i < rarray.length; i++) { console.log(val[i]) } }) done(); ``` ### encodeToString⁸⁺ encodeToString\(src:Uint8Array\):Promise Encodes the input content asynchronously into a string. - Parameters

Name	Type	Mandatory	Description
src	Uint8Array	Yes	Uint8Array to encode asynchronously.

- Return values

Type	Description
Promise<string>	String obtained after asynchronous encoding.

- Example ``` var that = new util.Base64(); var array = new Uint8Array([115,49,51]); await that.encodeToString(array).then(val=>{ console.log(val) }) done(); ``` ### decode⁸⁺ decode\(src:Uint8Array | string\):Promise Decodes the input content asynchronously. - Parameters

Name	Type	Mandatory	Description
src	Uint8Array \| string	Yes	Uint8Array or string to decode asynchronously.

- Return values

Type	Description
Promise<Uint8Array>	Uint8Array obtained after asynchronous decoding.

- Example ``` var that = new util.Base64(); var array = new Uint8Array([99,122,69,122]); var rarray = new Uint8Array([115,49,51]); await that.decode(array).then(val=>{ for (var i = 0; i < rarray.length; i++) { console.log(val[i]) } }) done(); ``` ## Types⁸⁺ ### constructor⁸⁺ constructor\(\) A constructor used to create a **Types** object. - Example ``` var type = new util.Types(); ``` ### isAnyArrayBuffer⁸⁺ isAnyArrayBuffer\(value: Object\):boolean Checks whether the input value is of the **ArrayBuffer** type. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is of the ArrayBuffer type; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isAnyArrayBuffer(new ArrayBuffer([])); ``` ### isArrayBufferView⁸⁺ isArrayBufferView\(value: Object\):boolean Checks whether the input value is of the **ArrayBufferView** type. **ArrayBufferView** is a helper type representing any of the following: **Int8Array**, **Int16Array**, **Int32Array**, **Uint8Array**, **Uint8ClampedArray**, **Uint32Array**, **Float32Array**, **Float64Array**, and **DataView**. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

Return values

Type	Description
boolean	Returns true if the input value is of the ArrayBufferView type; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isArrayBufferView(new Int8Array([])); ``` ### isArgumentsObject⁸⁺ isArgumentsObject\(value: Object\):boolean Checks whether the input value is of the **arguments** type. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is of the arguments type; returns false otherwise.

- Example ``` var that = new util.Types(); function foo() { var result = that.isArgumentsObject(arguments); } var f = foo(); ``` ### isArrayBuffer⁸⁺ isArrayBuffer\(value: Object\):boolean Checks whether the input value is of the **ArrayBuffer** type. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is of the ArrayBuffer type; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isArrayBuffer(new ArrayBuffer([])); ``` ### isAsyncFunction⁸⁺ isAsyncFunction\(value: Object\):boolean Checks whether the input value is an asynchronous function. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is an asynchronous function; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isAsyncFunction(async function foo() {}); ``` ### isBooleanObject⁸⁺ isBooleanObject\(value: Object\):boolean Checks whether the input value is of the **Boolean** type. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is of the Boolean type; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isBooleanObject(new Boolean(true)); ``` ### isBoxedPrimitive⁸⁺ isBoxedPrimitive\(value: Object\):boolean Checks whether the input value is of the **Boolean**, **Number**, **String**, or **Symbol** type. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is of the Boolean, Number, String, or Symbol type; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isBoxedPrimitive(new Boolean(false)); ``` ### isDataView⁸⁺ isDataView\(value: Object\):boolean Checks whether the input value is of the **DataView** type. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is of the DataView type; returns false otherwise.

- Example ``` var that = new util.Types(); const ab = new ArrayBuffer(20); var result = that.isDataView(new DataView(ab)); ``` ### isDate⁸⁺ isDate\(value: Object\):boolean Checks whether the input value is of the **Date** type. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is of the Data type; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isDate(new Date()); ``` ### isExternal⁸⁺ isExternal\(value: Object\):boolean Checks whether the input value is of the **native external** type. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is of the native external type; returns false otherwise.

- Example ``` var that = new util.Types(); const data = util.createExternalType(); var result = that.isExternal(data); ``` ### isFloat32Array⁸⁺ isFloat32Array\(value: Object\):boolean Checks whether the input value is of the **Float32Array** type. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is of the Float32Array type; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isFloat32Array(new Float32Array()); ``` ### isFloat64Array⁸⁺ isFloat64Array\(value: Object\):boolean Checks whether the input value is of the **Float64Array** type. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is of the Float64Array type; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isFloat64Array(new Float64Array()); ``` ### isGeneratorFunction⁸⁺ isGeneratorFunction\(value: Object\):boolean Checks whether the input value is a generator function. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is a generator function; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isGeneratorFunction(function* foo() {}); ``` ### isGeneratorObject⁸⁺ isGeneratorObject\(value: Object\):boolean Checks whether the input value is a generator object. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is a generator object; returns false otherwise.

- Example ``` var that = new util.Types(); function* foo() {} const generator = foo(); var result = that.isGeneratorObject(generator); ``` ### isInt8Array⁸⁺ isInt8Array\(value: Object\):boolean Checks whether the input value is of the **Int8Array** type. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is of the Int8Array type; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isInt8Array(new Int8Array([])); ``` ### isInt16Array⁸⁺ isInt16Array\(value: Object\):boolean Checks whether the input value is of the **Int16Array** type. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is of the Int16Array type; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isInt16Array(new Int16Array([])); ``` ### isInt32Array⁸⁺ isInt32Array\(value: Object\):boolean Checks whether the input value is of the **Int32Array** type. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is of the Int32Array type; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isInt32Array(new Int32Array([])); ``` ### isMap⁸⁺ isMap\(value: Object\):boolean Checks whether the input value is of the **Map** type. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is of the Map type; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isMap(new Map()); ``` ### isMapIterator⁸⁺ isMapIterator\(value: Object\):boolean Checks whether the input value is of the **MapIterator** type. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is of the MapIterator type; returns false otherwise.

- Example ``` var that = new util.Types(); const map = new Map(); var result = that.isMapIterator(map.keys()); ``` ### isNativeError⁸⁺ isNativeError\(value: Object\):boolean Checks whether the input value is of the **Error** type. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is of the Error type; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isNativeError(new TypeError()); ``` ### isNumberObject⁸⁺ isNumberObject\(value: Object\):boolean Checks whether the input value is a number object. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is a number object; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isNumberObject(new Number(0)); ``` ### isPromise⁸⁺ isPromise\(value: Object\):boolean Checks whether the input value is a promise. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is a promise; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isPromise(Promise.resolve(1)); ``` ### isProxy⁸⁺ isProxy\(value: Object\):boolean Checks whether the input value is a proxy. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is a proxy; returns false otherwise.

- Example ``` var that = new util.Types(); const target = {}; const proxy = new Proxy(target, {}); var result = that.isProxy(proxy); ``` ### isRegExp⁸⁺ isRegExp\(value: Object\):boolean Checks whether the input value is of the **RegExp** type. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is of the RegExp type; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isRegExp(new RegExp('abc')); ``` ### isSet⁸⁺ isSet\(value: Object\):boolean Checks whether the input value is of the **Set** type. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is of the Set type; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isSet(new Set()); ``` ### isSetIterator⁸⁺ isSetIterator\(value: Object\):boolean Checks whether the input value is of the **SetIterator** type. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is of the SetIterator type; returns false otherwise.

- Example ``` var that = new util.Types(); const set = new Set(); var result = that.isSetIterator(set.keys()); ``` ### isStringObject⁸⁺ isStringObject\(value: Object\):boolean Checks whether the input value is a string object. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is a string object; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isStringObject(new String('foo')); ``` ### isSymbolObjec⁸⁺ isSymbolObjec\(value: Object\):boolean Checks whether the input value is a symbol object. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is a symbol object; returns false otherwise.

- Example ``` var that = new util.Types(); const symbols = Symbol('foo'); var result = that.isSymbolObject(Object(symbols)); ``` ### isTypedArray⁸⁺ isTypedArray\(value: Object\):boolean Checks whether the input value is of the **TypedArray** type. **TypedArray** is a helper type representing any of the following: **Int8Array**, **Int16Array**, **Int32Array**, **Uint8Array**, **Uint8ClampedArray**, **Uint16Array**, **Uint32Array**, **Float32Array**, **Float64Array**, and **DataView**. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is of the TypedArray type; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isTypedArray(new Float64Array([])); ``` ### isUint8Array⁸⁺ isUint8Array\(value: Object\):boolean Checks whether the input value is of the **Uint8Array** type. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is of the Uint8Array type; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isUint8Array(new Uint8Array([])); ``` ### isUint8ClampedArray⁸⁺ isUint8ClampedArray\(value: Object\):boolean Checks whether the input value is of the **Uint8ClampedArray** type. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is of the Uint8ClampedArray type; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isUint8ClampedArray(new Uint8ClampedArray([])); ``` ### isUint16Array⁸⁺ isUint16Array\(value: Object\):boolean Checks whether the input value is of the **Uint16Array** type. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is of the Uint16Array type; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isUint16Array(new Uint16Array([])); ``` ### isUint32Array⁸⁺ isUint32Array\(value: Object\):boolean Checks whether the input value is of the **Uint32Array** type. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is of the Uint32Array type; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isUint32Array(new Uint32Array([])); ``` ### isWeakMap⁸⁺ isWeakMap\(value: Object\):boolean Checks whether the input value is of the **WeakMap** type. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is of the WeakMap type; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isWeakMap(new WeakMap()); ``` ### isWeakSet⁸⁺ isWeakSet\(value: Object\):boolean Checks whether the input value is of the **WeakSet** type. - Parameters

Name	Type	Mandatory	Description
value	Object	Yes	Object to check.

- Return values

Type	Description
boolean	Returns true if the input value is of the WeakSet type; returns false otherwise.

- Example ``` var that = new util.Types(); var result = that.isWeakSet(new WeakSet()); ```