The Int8Array()
constructor creates a typed array of twos-complement 8-bit signed 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).
new Int8Array(); // new in ES2017 new Int8Array(length); new Int8Array(typedArray); new Int8Array(object); new Int8Array(buffer [, byteOffset [, length]]);
length
length
argument, an internal array buffer is created in memory, of size length
multiplied by BYTES_PER_ELEMENT
bytes, containing zeros.typedArray
typedArray
argument, which can be an object of any of the typed array types (such as Int32Array
), the typedArray
gets copied into a new typed array. Each value in typedArray
is converted to the corresponding type of the constructor before being copied into the new array. The length of the new typed array will be same as the length of the typedArray
argument.object
object
argument, a new typed array is created as if by the TypedArray.from()
method.buffer
, byteOffset
, length
buffer
, and optionally a byteOffset
and a length
argument, a new typed array view is created that views the specified ArrayBuffer
. The byteOffset
and length
parameters specify the memory range that will be exposed by the typed array view. If both are omitted, all of buffer
is viewed; if only length
is omitted, the remainder of buffer
is viewed.// From a length 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 // From an array var arr = new Int8Array([21,31]); console.log(arr[1]); // 31 // From another TypedArray var x = new Int8Array([21, 31]); var y = new Int8Array(x); console.log(y[0]); // 21 // From an ArrayBuffer var buffer = new ArrayBuffer(8); var z = new Int8Array(buffer, 1, 4); // From an iterable var iterable = function*(){ yield* [1,2,3]; }(); var int8 = new Int8Array(iterable); // Int8Array[1, 2, 3]
Specification |
---|
ECMAScript (ECMA-262) The definition of 'TypedArray constructors' in that specification. |
Desktop | ||||||
---|---|---|---|---|---|---|
Int8Array() constructor |
7 | 12 | 4 | 10 | 11.6 | 5.1 |
Constructor without arguments | 7 | 12 | 55 | 10 | 11.6 | 5.1 |
new Int8Array(iterable) |
39 | 14 | 52 | No | 26 | 10 |
Int8Array() without new throws |
7 | 14 | 44 | No | 15 | 5.1 |
Mobile | ||||||
---|---|---|---|---|---|---|
Int8Array() constructor |
4 | 18 | 4 | 12 | 4.2 | 1.0 |
Constructor without arguments | ≤37 | 18 | 55 | 12 | 5 | 1.0 |
new Int8Array(iterable) |
39 | 39 | 52 | 26 | 10 | 4.0 |
Int8Array() without new throws |
≤37 | 18 | 44 | 14 | 5 | 1.0 |
Server | |
---|---|
Int8Array() constructor |
0.10 |
Constructor without arguments | 0.10 |
new Int8Array(iterable) |
4.0.0 |
Int8Array() without new throws |
0.12 |
Starting with ECMAScript 2015, Int8Array
constructors require to be constructed with a new
operator. Calling a Int8Array
constructor as a function without new
, will throw a TypeError
from now on.
var dv = Int8Array([1, 2, 3]); // TypeError: calling a builtin Int8Array constructor // without new is forbidden
var dv = new Int8Array([1, 2, 3]);
© 2005–2018 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://wiki.developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int8Array/Int8Array