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
Name | Type | Mandatory | Description |
---|---|---|---|
format | string | Yes | Format of the string to print. |
...args | Object[] | No | Values to format. The formatted values will replace the wildcard in the string. If this parameter is not set, the first parameter is returned by default. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
errno | number | Yes | Error code generated. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
original | Function | Yes | Asynchronous function. |
Return value
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 fn() {
return 'hello world';
}
let cb = util.callbackWrapper(fn);
cb(1, (err, ret) => {
if (err) throw 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
Name | Type | Mandatory | Description |
---|---|---|---|
original | Function | Yes | Asynchronous function. |
Return value
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 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
Name | Type | Readable | Writable | Description |
---|---|---|---|---|
encoding | string | Yes | No | Encoding format. - Supported formats: utf-8. |
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. |
constructor
constructor(encoding?: string, options?: { fatal?: boolean; ignoreBOM?: boolean },)
A constructor used to create a TextDecoder object.
System capability: SystemCapability.Utils.Lang
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: Uint8Array, options?: { stream?: false }): string
Decodes the input content.
System capability: SystemCapability.Utils.Lang
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 value
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:");
var retStr = textDecoder.decode( result , {stream: false});
console.log("retStr = " + retStr);
TextEncoder
Attributes
System capability: SystemCapability.Utils.Lang
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.
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
Name | Type | Mandatory | Description |
---|---|---|---|
input | string | Yes | String to encode. |
Return value
Type | Description |
---|---|
Uint8Array | Encoded text. |
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
Name | Type | Mandatory | Description |
---|---|---|---|
input | string | Yes | String to encode. |
dest | Uint8Array | Yes | Uint8Array instance used to store the UTF-8 encoded text. |
Return value
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.
System capability: SystemCapability.Utils.Lang
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 based on the given string.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
rationalString | string | Yes | String used to create the RationalNumber object. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
another | RationalNumber | Yes | Object used to compare with this RationalNumber object. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
object | Object | Yes | Object used to compare with this RationalNumber object. |
Return value
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 two specified integers.
System capability: SystemCapability.Utils.Lang
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 value
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.
System capability: SystemCapability.Utils.Lang
Return value
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.
System capability: SystemCapability.Utils.Lang
Return value
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.
System capability: SystemCapability.Utils.Lang
Return value
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).
System capability: SystemCapability.Utils.Lang
Return value
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.
System capability: SystemCapability.Utils.Lang
Return value
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.
System capability: SystemCapability.Utils.Lang
Return value
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
System capability: SystemCapability.Utils.Lang
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.
System capability: SystemCapability.Utils.Lang
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
newCapacity | number | Yes | New capacity of the LruBuffer. |
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
Type | Description |
---|---|
string | String representation of this LruBuffer 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.
System capability: SystemCapability.Utils.Lang
Return value
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.
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
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.
System capability: SystemCapability.Utils.Lang
Return value
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.
System capability: SystemCapability.Utils.Lang
Return value
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.
System capability: SystemCapability.Utils.Lang
Return value
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.
System capability: SystemCapability.Utils.Lang
Return value
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.
System capability: SystemCapability.Utils.Lang
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
key | K | Yes | Key based on which the value is queried. |
Return value
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.
System capability: SystemCapability.Utils.Lang
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 value
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.
System capability: SystemCapability.Utils.Lang
Return value
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.
System capability: SystemCapability.Utils.Lang
Return value
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
Removes the specified key and its value from this buffer.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
key | K | Yes | Key to remove. |
Return value
Type | Description |
---|---|
V | undefind | Returns an Optional object containing the removed 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 removed.
System capability: SystemCapability.Utils.Lang
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 removed. |
value | V | Yes | Value removed. |
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
key | K | Yes | Key to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
key | K | Yes | Key of which the value is missing. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Return value
Type | Description |
---|---|
[K, V] | 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.
System capability: SystemCapability.Utils.Lang
Return value
Type | Description |
---|---|
[K, V] | 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 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
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.
System capability: SystemCapability.Utils.Lang
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
range | Scope | Yes | Scope specified. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
lowerObj | ScopeType | Yes | Lower limit. |
upperObj | ScopeType | Yes | Upper limit. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Return value
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.
System capability: SystemCapability.Utils.Lang
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
lowerObj | ScopeType | Yes | Lower limit. |
upperObj | ScopeType | Yes | Upper limit. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
range | Scope | Yes | Scope specified. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | ScopeType | Yes | Value specified. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | ScopeType | Yes | Value specified. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
range | Scope | Yes | Scope specified. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | ScopeType | Yes | Value specified. |
Return value
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.
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
Name | Type | Mandatory | Description |
---|---|---|---|
src | Uint8Array | Yes | Uint8Array to encode. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
src | Uint8Array | Yes | Uint8Array to encode. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
src | Uint8Array | string | Yes | Uint8Array or string to decode. |
Return value
Type | Description |
---|---|
Uint8Array | Uint8Array decoded. |
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
Name | Type | Mandatory | Description |
---|---|---|---|
src | Uint8Array | Yes | Uint8Array to encode asynchronously. |
Return value
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]);
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
Name | Type | Mandatory | Description |
---|---|---|---|
src | Uint8Array | Yes | Uint8Array to encode asynchronously. |
Return value
Type | Description |
---|---|
Promise<string> | String obtained after asynchronous encoding. |
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
Name | Type | Mandatory | Description |
---|---|---|---|
src | Uint8Array | string | Yes | Uint8Array or string to decode asynchronously. |
Return value
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]);
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
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
Type | Description |
---|---|
boolean | Returns true if the input value is of the Date 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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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+
isSymbolObject(value: Object): boolean
Checks whether the input value is a symbol object.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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.
System capability: SystemCapability.Utils.Lang
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
value | Object | Yes | Object to check. |
Return value
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());