The Uint8Array typed array represents an array of 8-bit unsigned integers. The contents are initialized to 0. Once established, you can reference elements in the array using the object's methods, or using standard array index syntax (that is, using bracket notation).

Syntax

Uint8Array(length);
Uint8Array(typedArray);
Uint8Array(object);
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
Length property whose value is 3.
Uint8Array.name
Returns the string value of the constructor name. In the case of the Uint8Array type: "Uint8Array".
Uint8Array.prototype
Prototype for the TypedArray objects.

Methods

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

Uint8Array prototype

All Uint8Array objects inherit from %TypedArray%.prototype.

Properties

Uint8Array.prototype.constructor
Returns the function that created an instance's prototype. This is the Uint8Array constructor by default.
Uint8Array.prototype.buffer Read only
Returns the ArrayBuffer referenced by the Uint8Array Fixed at construction time and thus read only.
Uint8Array.prototype.byteLength Read only
Returns the length (in bytes) of the Uint8Array from the start of its ArrayBuffer. Fixed at construction time and thus read only.
Uint8Array.prototype.byteOffset Read only
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 Read only
Returns the number of elements hold in the Uint8Array. Fixed at construction time and thus read only.

Methods

Uint8Array.prototype.copyWithin()
Copies a sequence of array elements within the array. See also Array.prototype.copyWithin().
Uint8Array.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().
Uint8Array.prototype.every()
Tests whether all elements in the array pass the test provided by a function. See also Array.prototype.every().
Uint8Array.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().
Uint8Array.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().
Uint8Array.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().
Uint8Array.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().
Uint8Array.prototype.forEach()
Calls a function for each element in the array. See also Array.prototype.forEach().
Uint8Array.prototype.includes()
Determines whether a typed array includes a certain element, returning true or false as appropriate. See also Array.prototype.includes().
Uint8Array.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().
Uint8Array.prototype.join()
Joins all elements of an array into a string. See also Array.prototype.join().
Uint8Array.prototype.keys()
Returns a new Array Iterator that contains the keys for each index in the array. See also Array.prototype.keys().
Uint8Array.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().
Uint8Array.prototype.map()
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() Unimplemented
Former non-standard version of Uint8Array.prototype.copyWithin().
Uint8Array.prototype.reduce()
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()
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()
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()
Extracts a section of an array and returns a new array. See also Array.prototype.slice().
Uint8Array.prototype.some()
Returns true if at least one element in this array satisfies the provided testing function. See also Array.prototype.some().
Uint8Array.prototype.sort()
Sorts the elements of an array in place and returns the array. See also Array.prototype.sort().
Uint8Array.prototype.subarray()
Returns a new Uint8Array from the given start and end element index.
Uint8Array.prototype.values()
Returns a new Array Iterator object that contains the values for each index in the array. See also Array.prototype.values().
Uint8Array.prototype.toLocaleString()
Returns a localized string representing the array and its elements. See also Array.prototype.toLocaleString().
Uint8Array.prototype.toString()
Returns a string representing the array and its elements. See also Array.prototype.toString().
Uint8Array.prototype[@@iterator]()
Returns a new Array Iterator object that contains the values for each index in the array.

Examples

// 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);

Specifications

Specification Status Comment
Typed Array Specification Obsolete Superseded by ECMAScript 6.
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'TypedArray constructors' in that specification.
Standard Initial definition in an ECMA standard.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support 7.0 4.0 (2) 10 11.6 5.1
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

See also

Document Tags and Contributors

Last updated by: fscholz,
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