Int8Array

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

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.prototype (en-US): 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 (en-US).

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() 实验性: 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。参见 Array.prototype.map()。
Int8Array.prototype.move() 非标准: 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

Specification
ECMAScript Language Specification # table-49

浏览器兼容性

BCD tables only load in the browser

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]);