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';

util.printf

printf(format: string, ...args: Object[]): string

Prints the input content in a formatted string.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return 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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

Example

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

TextDecoder

Attributes

System capability: SystemCapability.Utils.Lang

constructor

constructor(encoding?: string, options?: { fatal?: boolean; ignoreBOM?: boolean },)

A constructor used to create a TextDecoder object.

System capability: SystemCapability.Utils.Lang

Parameters

Table 1 options

Example

var textDecoder = new util.TextDecoder("utf-8",{ignoreBOM: true});

decode

decode(input: Uint8Array, options?: { stream?: false }): string

Decodes the input content.

System capability: SystemCapability.Utils.Lang

Parameters

Table 2 options

Return value

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:");
var retStr = textDecoder.decode( result , {stream: false});
console.log("retStr = " + retStr);

TextEncoder

Attributes

System capability: SystemCapability.Utils.Lang

constructor

constructor()

A constructor used to create a TextEncoder object.

System capability: SystemCapability.Utils.Lang

Example

var textEncoder = new util.TextEncoder();

encode

encode(input?: string): Uint8Array

Encodes the input content.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

Example

var textEncoder = new util.TextEncoder();
var buffer = new ArrayBuffer(20);
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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Example

var rationalNumber = new util.RationalNumber(1,2);

createRationalFromString⁸⁺

static createRationalFromString​(rationalString: string): RationalNumber​

Creates a RationalNumber object based on the given string.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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 two specified integers.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

Example

var rationalNumber = new util.RationalNumber(1,2);
var result = rationalNumber.getCommonDivisor(4,6);

getNumerator⁸⁺

getNumerator​(): number

Obtains the numerator of this RationalNumber object.

System capability: SystemCapability.Utils.Lang

Return value

Example

var rationalNumber = new util.RationalNumber(1,2);
var result = rationalNumber.getNumerator();

getDenominator⁸⁺

getDenominator​(): number

Obtains the denominator of this RationalNumber object.

System capability: SystemCapability.Utils.Lang

Return value

Example

var rationalNumber = new util.RationalNumber(1,2);
var result = rationalNumber.getDenominator();

isZero⁸⁺

isZero​():boolean

Checks whether this RationalNumber object is 0.

System capability: SystemCapability.Utils.Lang

Return value

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).

System capability: SystemCapability.Utils.Lang

Return value

Example

var rationalNumber = new util.RationalNumber(1,2);
var result = rationalNumber.isNaN();

isFinite⁸⁺

isFinite​():boolean

Checks whether this RationalNumber object represents a finite value.

System capability: SystemCapability.Utils.Lang

Return value

Example

var rationalNumber = new util.RationalNumber(1,2);
var result = rationalNumber.isFinite();

toString⁸⁺

toString​(): string

Obtains the string representation of this RationalNumber object.

System capability: SystemCapability.Utils.Lang

Return value

Example

var rationalNumber = new util.RationalNumber(1,2);
var result = rationalNumber.toString();

LruBuffer⁸⁺

Attributes

System capability: SystemCapability.Utils.Lang

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.

System capability: SystemCapability.Utils.Lang

Parameters

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.

System capability: SystemCapability.Utils.Lang

Parameters

Example

var pro = new util.LruBuffer();
var result = pro.updateCapacity(100);

toString⁸⁺

toString(): string

Obtains the string representation of this LruBuffer object.

System capability: SystemCapability.Utils.Lang

Return value

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.

System capability: SystemCapability.Utils.Lang

Return value

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.

System capability: SystemCapability.Utils.Lang

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().

System capability: SystemCapability.Utils.Lang

Return value

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.

System capability: SystemCapability.Utils.Lang

Return value

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.

System capability: SystemCapability.Utils.Lang

Return value

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.

System capability: SystemCapability.Utils.Lang

Return value

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.

System capability: SystemCapability.Utils.Lang

Return value

Example

var pro = new util.LruBuffer();
pro.put(2,10);
var result = pro.getPutCount();

isEmpty⁸⁺

isEmpty(): boolean

Checks whether this buffer is empty.

System capability: SystemCapability.Utils.Lang

Return 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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Return value

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.

System capability: SystemCapability.Utils.Lang

Return value

Example

var pro = new util.LruBuffer();
pro.put(2,10);
var result = pro.keys();

remove⁸⁺

remove(key: K): V | undefined

Removes the specified key and its value from this buffer.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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 removed.

System capability: SystemCapability.Utils.Lang

Parameters

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Return value

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.

System capability: SystemCapability.Utils.Lang

Return value

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 object.

Example

class Temperature{
    constructor(value){
       // If TS is used for development, add the following code:
       // private readonly _temp: Temperature;
       this._temp = value;
    }
    comapreTo(value){
       return this._temp >= value.getTemp();
    }
    getTemp(){
       return this._temp;
    }
    toString(){
       return this._temp.toString();
    }
}

constructor⁸⁺

constructor(lowerObj: ScopeType, upperObj: ScopeType)

A constructor used to create a Scope object with the specified upper and lower limits.

System capability: SystemCapability.Utils.Lang

Parameters

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.

System capability: SystemCapability.Utils.Lang

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Return value

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.

System capability: SystemCapability.Utils.Lang

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return 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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return 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.clamp(tempMiDF);

Base64⁸⁺

constructor⁸⁺

constructor()

A constructor used to create a Base64 object.

System capability: SystemCapability.Utils.Lang

Example

var base64 = new  util.Base64();

encodeSync⁸⁺

encodeSync(src: Uint8Array): Uint8Array

Encodes the input content.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

Example

var that = new util.Base64();
var buff = 'czEz';
var result = that.decodeSync(buff);

encode⁸⁺

encode(src: Uint8Array): Promise<Uint8Array>

Encodes the input content asynchronously.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

Example

var that = new util.Base64();
var array = new Uint8Array([115,49,51]);
var rarray = new Uint8Array([99,122,69,122]);
that.encode(array).then(val=>{    
    for (var i = 0; i < rarray.length; i++) {        
        console.log(val[i])
    }
})

encodeToString⁸⁺

encodeToString(src: Uint8Array): Promise<string>

Encodes the input content asynchronously.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

Example

var that = new util.Base64();
var array = new Uint8Array([115,49,51]);
that.encodeToString(array).then(val=>{    
    console.log(val)
})

decode⁸⁺

decode(src: Uint8Array | string): Promise<Uint8Array>

Decodes the input content asynchronously.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

Example

var that = new util.Base64();
var array = new Uint8Array([99,122,69,122]);
var rarray = new Uint8Array([115,49,51]);
that.decode(array).then(val=>{    
    for (var i = 0; i < rarray.length; i++) {        
        console.log(val[i])
    }
})

types⁸⁺

constructor⁸⁺

constructor()

A constructor used to create a Types object.

System capability: SystemCapability.Utils.Lang

Example

var type = new util.types();

isAnyArrayBuffer⁸⁺

isAnyArrayBuffer(value: Object): boolean

Checks whether the input value is of the ArrayBuffer type.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

Example

var that = new util.types();
var result = that.isStringObject(new String('foo'));

isSymbolObjec⁸⁺

isSymbolObject(value: Object): boolean

Checks whether the input value is a symbol object.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

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.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

Example

var that = new util.types();
var result = that.isWeakSet(new WeakSet());