Int8Array - JavaScript 编辑

Int8Array 类型数组表示二进制补码8位有符号整数的数组。内容初始化为0。 一旦建立，你可以使用对象的方法引用数组中的元素，或使用标准数组索引语法( 即，使用括号注释)。

语法

new Int8Array(length);
new Int8Array(typedArray);
new Int8Array(object);
new Int8Array(buffer [, byteOffset [, length]]);

有关构造函数语法和参数的更多信息，请访问 TypedArray.

属性

Int8Array.BYTES_PER_ELEMENT

返回数组中每个元素的大小. 在Int8Array中这个值为1.

Int8Array.length

此属性为固定值属性，值为3.查看 Int8Array.prototype.length获得获取数组内元素个数方法。

Int8Array.name

返回构造器方法名称.在Int8Array类型中此值为 "Int8Array"。

Int8Array.prototype

TypedArray 对象的构造原型。

方法

Int8Array.from()

从类数组对象或迭代器生成int8Array数组对象. 参照Array.from().

Int8Array.of()

以多个参数构造Int8Array对象， 参照 Array.of().

Int8Array 原型方法

所有 Int8Array对象都继承自 %TypedArray%.prototype.

属性

Int8Array.prototype.constructor

这个方法会返回对象的构造原型. 默认为Int8Array构造函数.

Int8Array.prototype.buffer 只读

Returns the ArrayBuffer referenced by the Int8Array Fixed at construction time and thus read only.

Int8Array.prototype.byteLength 只读

Returns the length (in bytes) of the Int8Array from the start of its ArrayBuffer. Fixed at construction time and thus read only.

Int8Array.prototype.byteOffset 只读

Returns the offset (in bytes) of the Int8Array from the start of its ArrayBuffer. Fixed at construction time and thus read only.

Int8Array.prototype.length 只读

Returns the number of elements hold in the Int8Array. Fixed at construction time and thus read only.

方法

Int8Array.prototype.copyWithin()

Copies a sequence of array elements within the array. See also Array.prototype.copyWithin().

Int8Array.prototype.entries()

Returns a new Array Iterator object that contains the key/value pairs for each index in the array. See also Array.prototype.entries().

Int8Array.prototype.every()

Tests whether all elements in the array pass the test provided by a function. See also Array.prototype.every().

Int8Array.prototype.fill()

Fills all the elements of an array from a start index to an end index with a static value. See also Array.prototype.fill().

Int8Array.prototype.filter()

Creates a new array with all of the elements of this array for which the provided filtering function returns true. See also Array.prototype.filter().

Int8Array.prototype.find()

Returns the found value in the array, if an element in the array satisfies the provided testing function or undefined if not found. See also Array.prototype.find().

Int8Array.prototype.findIndex()

Returns the found index in the array, if an element in the array satisfies the provided testing function or -1 if not found. See also Array.prototype.findIndex().

Int8Array.prototype.forEach()

Calls a function for each element in the array. See also Array.prototype.forEach().

Int8Array.prototype.includes()

Determines whether a typed array includes a certain element, returning true or false as appropriate. See also Array.prototype.includes().

Int8Array.prototype.indexOf()

Returns the first (least) index of an element within the array equal to the specified value, or -1 if none is found. See also Array.prototype.indexOf().

Int8Array.prototype.join()

Joins all elements of an array into a string. See also Array.prototype.join().

Int8Array.prototype.keys()

Returns a new Array Iterator that contains the keys for each index in the array. See also Array.prototype.keys().

Int8Array.prototype.lastIndexOf()

Returns the last (greatest) index of an element within the array equal to the specified value, or -1 if none is found. See also Array.prototype.lastIndexOf().

Int8Array.prototype.map()

返回一个由回调函数的返回值组成的新数组。. See also Array.prototype.map().

Int8Array.prototype.move() 未实现

Int8Array.prototype.copyWithin() 早期的不标准定义。

Int8Array.prototype.reduce()

从左到右为每个数组元素执行一次回调函数，并把上次回调函数的返回值放在一个暂存器中传给下次回调函数，并返回最后一次回调函数的返回值。参照 Array.prototype.reduce().

Int8Array.prototype.reduceRight()

从右到左为每个数组元素执行一次回调函数，并把上次回调函数的返回值放在一个暂存器中传给下次回调函数，并返回最后一次回调函数的返回值。参照 Array.prototype.reduceRight().

Int8Array.prototype.reverse()

颠倒数组中元素的排列顺序，即原先的第一个变为最后一个，原先的最后一个变为第一个。参照Array.prototype.reverse().

Int8Array.prototype.set()

Stores multiple values in the typed array, reading input values from a specified array.

Int8Array.prototype.slice()

抽取当前数组中的一段元素组合成一个新数组。参照Array.prototype.slice().

Int8Array.prototype.some()

如果数组中至少有一个元素满足测试函数，则返回 true，否则返回 false。参照 Array.prototype.some().

Int8Array.prototype.sort()

对数组元素进行排序，并返回当前数组. 参照Array.prototype.sort().

Int8Array.prototype.subarray()

返回一个以给定的初始结束位置裁剪的Int8Array数组.

Int8Array.prototype.values()

返回一个数组迭代器对象，该迭代器会包含所有数组元素的值。. 参照 Array.prototype.values().

Int8Array.prototype.toLocaleString()

返回一个由所有数组元素组合而成的本地化后的字符串. See also Array.prototype.toLocaleString().

Int8Array.prototype.toString()

返回一个由所有数组元素组合而成的字符串.参照 Array.prototype.toString().

Int8Array.prototype[@@iterator]()

此方法返回一个带有数组内所有元素的迭代器对象，同Int8Array.prototype.values 。

示例

// 以长度参数构造对象
var int8 = new Int8Array(2);
int8[0] = 42;
console.log(int8[0]); // 42
console.log(int8.length); // 2
console.log(int8.BYTES_PER_ELEMENT); // 1

// 以数组构造对象
var arr = new Int8Array([21,31]);
console.log(arr[1]); // 31

// 从另一数组构造对象
var x = new Int8Array([21, 31]);
var y = new Int8Array(x);
console.log(y[0]); // 21

// 从ArrayBuffer构造对象
var buffer = new ArrayBuffer(8);
var z = new Int8Array(buffer, 1, 4);

规范

规范	状态	评论
Typed Array Specification	Obsolete	已被 ECMAScript 6取代。
ECMAScript 2015 (6th Edition, ECMA-262) TypedArray constructors	Standard	ECMA 标准中构造对象时 new 关键字为必需。
ECMAScript Latest Draft (ECMA-262) TypedArray constructors	Draft

浏览器兼容性

We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help!

• Desktop
• Mobile

功能	Chrome	Firefox (Gecko)	Internet Explorer	Opera	Safari
Basic support	7.0	4.0 (2)	10	11.6	5.1
new is required	?	44 (44)	?	?	?

Feature	Android	Chrome for Android	Firefox Mobile (Gecko)	IE Mobile	Opera Mobile	Safari Mobile
Basic support	4.0	(Yes)	4.0 (2)	10	11.6	4.2
new is required	?	?	44.0 (44)	?	?	?

兼容性说明

自 ECMAScript 2015 (ES6)施行, Int8Array 需要使用new 构造. 从当前版本开始，不加new而便调用Int8Array 构造器方法, 将报出 TypeError 错误.

var dv = Int8Array([1, 2, 3]);
// TypeError: calling a builtin Int8Array constructor
// without new is forbidden

var dv = new Int8Array([1, 2, 3]);

相关链接

• JavaScript typed arrays
• ArrayBuffer
• DataView