Uint8Array

Объект Uint8Array представляет типизированный массив 8-разрядных целых беззнаковых значений. Содержимое инициализируется значением 0. Создав экземпляр Uint8Array, возможно получить доступ к элементам массива, используя методы объекта или стандартный синтаксис доступа к элементу массива по его индексу (с помощью скобочной нотации).

Syntax

new Uint8Array(); // new in ES2017
new Uint8Array(length);
new Uint8Array(typedArray);
new Uint8Array(object);
new Uint8Array(buffer [, byteOffset [, length]]);

For more information about the constructor syntax and the parameters, see TypedArray.

Properties

Uint8Array.BYTES_PER_ELEMENT: Returns a number value of the element size. 1 in the case of an Uint8Array.
Uint8Array.length: Static length property whose value is 0. For the actual length (number of elements), see Uint8Array.prototype.length (en-US).
Uint8Array.name (en-US): Returns the string value of the constructor name. In the case of the Uint8Array type: "Uint8Array".
Uint8Array.prototype (en-US): Prototype for the TypedArray objects.

Methods

Uint8Array.from() (en-US): Creates a new Uint8Array from an array-like or iterable object. See also Array.from().
Uint8Array.of() (en-US): Creates a new Uint8Array with a variable number of arguments. See also Array.of().

`Uint8Array` prototype

All Uint8Array objects inherit from %TypedArray%.prototype (en-US).

Properties

Uint8Array.prototype.constructor: Returns the function that created an instance's prototype. This is the Uint8Array constructor by default.
Uint8Array.prototype.buffer (en-US) Только для чтения: Returns the ArrayBuffer referenced by the Uint8Array Fixed at construction time and thus read only.
Uint8Array.prototype.byteLength (en-US) Только для чтения: Returns the length (in bytes) of the Uint8Array. Fixed at construction time and thus read only.
Uint8Array.prototype.byteOffset (en-US) Только для чтения: Returns the offset (in bytes) of the Uint8Array from the start of its ArrayBuffer. Fixed at construction time and thus read only.
Uint8Array.prototype.length (en-US) Только для чтения: Returns the number of elements held in the Uint8Array. Fixed at construction time and thus read only.

Methods

Uint8Array.prototype.copyWithin() (en-US): Copies a sequence of array elements within the array. See also Array.prototype.copyWithin().
Uint8Array.prototype.entries() (en-US): Returns a new Array Iterator object that contains the key/value pairs for each index in the array. See also Array.prototype.entries().
Uint8Array.prototype.every() (en-US): Tests whether all elements in the array pass the test provided by a function. See also Array.prototype.every().
Uint8Array.prototype.fill() (en-US): Fills all the elements of an array from a start index to an end index with a static value. See also Array.prototype.fill().
Uint8Array.prototype.filter() (en-US): 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().
Uint8Array.prototype.find() (en-US): 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().
Uint8Array.prototype.findIndex() (en-US): 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().
Uint8Array.prototype.forEach() (en-US): Calls a function for each element in the array. See also Array.prototype.forEach().
Uint8Array.prototype.includes() (en-US) Экспериментальная возможность: Determines whether a typed array includes a certain element, returning true or false as appropriate. See also Array.prototype.includes().
Uint8Array.prototype.indexOf() (en-US): 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().
Uint8Array.prototype.join(): Joins all elements of an array into a string. See also Array.prototype.join().
Uint8Array.prototype.keys() (en-US): Returns a new Array Iterator that contains the keys for each index in the array. See also Array.prototype.keys().
Uint8Array.prototype.lastIndexOf() (en-US): 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().
Uint8Array.prototype.map() (en-US): Creates a new array with the results of calling a provided function on every element in this array. See also Array.prototype.map().
Uint8Array.prototype.move() Non-standard Не реализовано: Former non-standard version of Uint8Array.prototype.copyWithin() (en-US).
Uint8Array.prototype.reduce() (en-US): Apply a function against an accumulator and each value of the array (from left-to-right) as to reduce it to a single value. See also Array.prototype.reduce().
Uint8Array.prototype.reduceRight() (en-US): Apply a function against an accumulator and each value of the array (from right-to-left) as to reduce it to a single value. See also Array.prototype.reduceRight().
Uint8Array.prototype.reverse() (en-US): Reverses the order of the elements of an array — the first becomes the last, and the last becomes the first. See also Array.prototype.reverse().
Uint8Array.prototype.set(): Stores multiple values in the typed array, reading input values from a specified array.
Uint8Array.prototype.slice() (en-US): Extracts a section of an array and returns a new array. See also Array.prototype.slice().
Uint8Array.prototype.some() (en-US): Returns true if at least one element in this array satisfies the provided testing function. See also Array.prototype.some().
Uint8Array.prototype.sort() (en-US): Sorts the elements of an array in place and returns the array. See also Array.prototype.sort().
Uint8Array.prototype.subarray() (en-US): Returns a new Uint8Array from the given start and end element index.
Uint8Array.prototype.values() (en-US): Returns a new Array Iterator object that contains the values for each index in the array. See also Array.prototype.values().
Uint8Array.prototype.toLocaleString() (en-US): Returns a localized string representing the array and its elements. See also Array.prototype.toLocaleString().
Uint8Array.prototype.toString() (en-US): Returns a string representing the array and its elements. See also Array.prototype.toString().
Uint8Array.prototype[@@iterator]() (en-US): Returns a new Array Iterator object that contains the values for each index in the array.

Examples

Different ways to create a Uint8Array:

// From a length
var uint8 = new Uint8Array(2);
uint8[0] = 42;
console.log(uint8[0]); // 42
console.log(uint8.length); // 2
console.log(uint8.BYTES_PER_ELEMENT); // 1

// From an array
var arr = new Uint8Array([21,31]);
console.log(arr[1]); // 31

// From another TypedArray
var x = new Uint8Array([21, 31]);
var y = new Uint8Array(x);
console.log(y[0]); // 21

// From an ArrayBuffer
var buffer = new ArrayBuffer(8);
var z = new Uint8Array(buffer, 1, 4);

// From an iterable
var iterable = function*(){ yield* [1,2,3]; }();
var uint8 = new Uint8Array(iterable);
// Uint8Array[1, 2, 3]

Specifications

Specification	Status	Comment
Typed Array Specification	Устаревшая	Superseded by ECMAScript 6.
ECMAScript 2015 (6th Edition, ECMA-262) Определение 'TypedArray constructors' в этой спецификации.	Стандарт	Initial definition in an ECMA standard. Specified that `new` is required.
ECMAScript (ECMA-262) Определение 'TypedArray constructors' в этой спецификации.	Живой стандарт	ECMAScript 2017 changed the `Uint8Array` constructor to use the `ToIndex` operation and allows constructors with no arguments.

Browser compatibility

BCD tables only load in the browser

Compatibility notes

Starting with ECMAScript 2015, Uint8Array constructors require to be constructed with a new operator. Calling a Uint8Array constructor as a function without new, will throw a TypeError from now on.

var dv = Uint8Array([1, 2, 3]);
// TypeError: calling a builtin Uint8Array constructor
// without new is forbidden

var dv = new Uint8Array([1, 2, 3]);