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TypedArrays

大约 5 分钟featurees-standard

TypedArrays

针对 ArrayBuffer、DataView、Typed Array 构造函数、静态和圆形方法的实现和修复。Typed arrays 只在支持解释器的环境（IE9+）中工作，ArrayBuffer 和 DataView 支持所有环境。

模块

类型

class ArrayBuffer {
  constructor(length: number);
  slice(start: number, end: number): ArrayBuffer;
  readonly byteLength: number;
  static isView(arg: any): boolean;
}

class DataView {
  constructor(buffer: ArrayBuffer, byteOffset?: number, byteLength?: number);
  getInt8(offset: any): number;
  getUint8(offset: any): number;
  /**@param littleEndian @default false */
  getInt16(offset: any, littleEndian?: boolean): number;
  /**@param littleEndian @default false */
  getUnumber(offset: any, littleEndian?: boolean): number;
  /**@param littleEndian @default false */
  getInt32(offset: any, littleEndian?: boolean): number;
  /**@param littleEndian @default false */
  getUint32(offset: any, littleEndian?: boolean): number;
  /**@param littleEndian @default false */
  getFloat32(offset: any, littleEndian?: boolean): number;
  /**@param littleEndian @default false */
  getFloat64(offset: any, littleEndian?: boolean): number;
  setInt8(offset: any, value: any): void;
  setUint8(offset: any, value: any): void;
  /**@param littleEndian @default false */
  setInt16(offset: any, value: any, littleEndian?: boolean): void;
  /**@param littleEndian @default false */
  setUint16(offset: any, value: any, littleEndian?: boolean): void;
  /**@param littleEndian @default false */
  setInt32(offset: any, value: any, littleEndian?: boolean): void;
  /**@param littleEndian @default false */
  setUint32(offset: any, value: any, littleEndian?: boolean): void;
  /**@param littleEndian @default false */
  setFloat32(offset: any, value: any, littleEndian?: boolean): void;
  /**@param littleEndian @default false */
  setFloat64(offset: any, value: any, littleEndian?: boolean): void;
  readonly buffer: ArrayBuffer;
  readonly byteLength: number;
  readonly byteOffset: number;
}

abstract class TypedArray {
  constructor(length: number);
  constructor(object: TypedArray | Iterable<number> | ArrayLike<number>);
  constructor(buffer: ArrayBuffer, byteOffset?: number, length?: number);
  static from(
    items: Iterable<number> | ArrayLike<number>,
    mapFn?: (value: any, index: number) => any,
    thisArg?: any
  ): TypedArray;
  static of(...args: Array<number>): TypedArray;
  BYTES_PER_ELEMENT: number;
  abstract at(index: number): number;
  abstract copyWithin(target: number, start: number, end?: number): this;
  abstract entries(): Iterator<[number, number]>;
  abstract every(
    callbackfn: (value: number, index: number, target: TypedArray) => boolean,
    thisArg?: any
  ): boolean;
  abstract fill(value: number, start?: number, end?: number): this;
  abstract filter(
    callbackfn: (value: number, index: number, target: TypedArray) => boolean,
    thisArg?: any
  ): TypedArray;
  abstract find(
    callbackfn: (value: number, index: number, target: TypedArray) => boolean,
    thisArg?: any
  ): any;
  abstract findIndex(
    callbackfn: (value: number, index: number, target: TypedArray) => boolean,
    thisArg?: any
  ): number;
  abstract findLast(
    callbackfn: (value: any, index: number, target: TypedArray) => boolean,
    thisArg?: any
  ): any;
  abstract findLastIndex(
    callbackfn: (value: any, index: number, target: TypedArray) => boolean,
    thisArg?: any
  ): number;
  abstract forEach(
    callbackfn: (value: number, index: number, target: TypedArray) => void,
    thisArg?: any
  ): void;
  abstract includes(searchElement: any, from?: number): boolean;
  abstract indexOf(searchElement: any, from?: number): number;
  /**@param separator @default ','*/
  abstract join(separator: string): string;
  abstract keys(): Iterator<number>;
  abstract lastIndexOf(searchElement: any, from?: number): number;
  abstract map(
    mapFn: (value: number, index: number, target: TypedArray) => number,
    thisArg?: any
  ): TypedArray;
  abstract reduce(
    callbackfn: (
      memo: any,
      value: number,
      index: number,
      target: TypedArray
    ) => any,
    initialValue?: any
  ): any;
  abstract reduceRight(
    callbackfn: (
      memo: any,
      value: number,
      index: number,
      target: TypedArray
    ) => any,
    initialValue?: any
  ): any;
  abstract reverse(): this;
  abstract set(array: ArrayLike<any>, offset?: number): void;
  abstract slice(start?: number, end?: number): TypedArray;
  abstract some(
    callbackfn: (value: number, index: number, target: TypedArray) => boolean,
    thisArg?: any
  ): boolean;
  abstract sort(comparefn?: (a: number, b: number) => number): this; // with modern behavior like stable sort
  abstract subarray(begin?: number, end?: number): TypedArray;
  abstract toReversed(): TypedArray;
  abstract toSorted(comparefn?: (a: any, b: any) => number): TypedArray;
  abstract toString(): string;
  abstract toLocaleString(): string;
  abstract values(): Iterator<number>;
  abstract with(index: number, value: any): TypedArray;
  [Symbol.iterator](): Iterator<number>;
  readonly buffer: ArrayBuffer;
  readonly byteLength: number;
  readonly byteOffset: number;
  readonly length: number;
  BYTES_PER_ELEMENT: number;
}
interface TypedArrayConstructor {}

class Int8Array extends TypedArray {}
class Uint8Array extends TypedArray {}
class Int16Array extends TypedArray {}
class Uint16Array extends TypedArray {}
class Int32Array extends TypedArray {}
class Uint32Array extends TypedArray {}
class Float32Array extends TypedArray {}
class Float64Array extends TypedArray {}

入口点

core-js/es|stable|actual|full/array-buffer
core-js/es|stable|actual|full/array-buffer/constructor
core-js/es|stable|actual|full/array-buffer/is-view
core-js/es|stable|actual|full/array-buffer/slice
core-js/es|stable|actual|full/data-view
core-js/es|stable|actual|full/typed-array
core-js/es|stable|actual|full/typed-array/int8-array
core-js/es|stable|actual|full/typed-array/uint8-array
core-js/es|stable|actual|full/typed-array/uint8-clamped-array
core-js/es|stable|actual|full/typed-array/int16-array
core-js/es|stable|actual|full/typed-array/uint16-array
core-js/es|stable|actual|full/typed-array/int32-array
core-js/es|stable|actual|full/typed-array/uint32-array
core-js/es|stable|actual|full/typed-array/float32-array
core-js/es|stable|actual|full/typed-array/float64-array
core-js/es|stable|actual|full/typed-array/at
core-js/es|stable|actual|full/typed-array/copy-within
core-js/es|stable|actual|full/typed-array/entries
core-js/es|stable|actual|full/typed-array/every
core-js/es|stable|actual|full/typed-array/fill
core-js/es|stable|actual|full/typed-array/filter
core-js/es|stable|actual|full/typed-array/find
core-js/es|stable|actual|full/typed-array/find-index
core-js/es|stable|actual|full/typed-array/find-last
core-js/es|stable|actual|full/typed-array/find-last-index
core-js/es|stable|actual|full/typed-array/for-each
core-js/es|stable|actual|full/typed-array/from
core-js/es|stable|actual|full/typed-array/includes
core-js/es|stable|actual|full/typed-array/index-of
core-js/es|stable|actual|full/typed-array/iterator
core-js/es|stable|actual|full/typed-array/join
core-js/es|stable|actual|full/typed-array/keys
core-js/es|stable|actual|full/typed-array/last-index-of
core-js/es|stable|actual|full/typed-array/map
core-js/es|stable|actual|full/typed-array/of
core-js/es|stable|actual|full/typed-array/reduce
core-js/es|stable|actual|full/typed-array/reduce-right
core-js/es|stable|actual|full/typed-array/reverse
core-js/es|stable|actual|full/typed-array/set
core-js/es|stable|actual|full/typed-array/slice
core-js/es|stable|actual|full/typed-array/some
core-js/es|stable|actual|full/typed-array/sort
core-js/es|stable|actual|full/typed-array/subarray
core-js/es|stable|actual|full/typed-array/to-locale-string
core-js/es|stable|actual|full/typed-array/to-string
core-js/es|stable|actual|full/typed-array/values

示例

示例open in new window:

new Int32Array(4); // => [0, 0, 0, 0]
new Uint8ClampedArray([1, 2, 3, 666]); // => [1, 2, 3, 255]
new Float32Array(new Set([1, 2, 3, 2, 1])); // => [1, 2, 3]

let buffer = new ArrayBuffer(8);
let view = new DataView(buffer);
view.setFloat64(0, 123.456, true);
new Uint8Array(buffer.slice(4)); // => [47, 221, 94, 64]

Int8Array.of(1, 1.5, 5.7, 745); // => [1, 1, 5, -23]
Uint8Array.from([1, 1.5, 5.7, 745]); // => [1, 1, 5, 233]

let typed = new Uint8Array([1, 2, 3]);

let a = typed.slice(1); // => [2, 3]
typed.buffer === a.buffer; // => false
let b = typed.subarray(1); // => [2, 3]
typed.buffer === b.buffer; // => true

typed.filter((it) => it % 2); // => [1, 3]
typed.map((it) => it * 1.5); // => [1, 3, 4]

for (let value of typed) console.log(value); // => 1, 2, 3
for (let value of typed.values()) console.log(value); // => 1, 2, 3
for (let key of typed.keys()) console.log(key); // => 0, 1, 2
for (let [key, value] of typed.entries()) {
  console.log(key); // => 0, 1, 2
  console.log(value); // => 1, 2, 3
}

new Int32Array([1, 2, 3]).at(1); // => 2
new Int32Array([1, 2, 3]).at(-1); // => 3

使用 typed arrays polyfills 时的注意事项：

  • Typed Arrays 构造函数的 polyfill 完全按照规范预期的方式工作，但是很慢而且显著消耗内存，因为每个实例内部使用的 getter 和 setter。但是 Typed Arrays 构造函数的 polyfill 主要用于老 IE，所有现代引擎有原生的 Typed Arrays 构造函数，只需要针对构造函数的修复和针对方法的 polyfill。
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