The Uint8ClampedArray()
constructor creates a typed array of 8-bit unsigned integers clamped to 0-255; if you specified a value that is out of the range of [0,255], 0 or 255 will be set instead; if you specify a non-integer, the nearest integer will be set. 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 Uint8ClampedArray(); // new in ES2017 new Uint8ClampedArray(length); new Uint8ClampedArray(typedArray); new Uint8ClampedArray(object); new Uint8ClampedArray(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 uintc8 = new Uint8ClampedArray(2); uintc8[0] = 42; uintc8[1] = 1337; console.log(uintc8[0]); // 42 console.log(uintc8[1]); // 255 (clamped) console.log(uintc8.length); // 2 console.log(uintc8.BYTES_PER_ELEMENT); // 1 // From an array var arr = new Uint8ClampedArray([21,31]); console.log(arr[1]); // 31 // From another TypedArray var x = new Uint8ClampedArray([21, 31]); var y = new Uint8ClampedArray(x); console.log(y[0]); // 21 // From an ArrayBuffer var buffer = new ArrayBuffer(8); var z = new Uint8ClampedArray(buffer, 1, 4); // From an iterable var iterable = function*(){ yield* [1,2,3]; }(); var uintc8 = new Uint8ClampedArray(iterable); // Uint8ClampedArray[1, 2, 3]
Specification |
---|
ECMAScript (ECMA-262) The definition of 'TypedArray constructors' in that specification. |
Desktop | ||||||
---|---|---|---|---|---|---|
Uint8ClampedArray() constructor |
7 | 12 | 4 | 10 | 11.6 | 5.1 |
Constructor without arguments | 7 | 12 | 55 | 10 | 11.6 | 5.1 |
new Uint8ClampedArray(iterable) |
39 | 14 | 52 | No | 26 | 10 |
Uint8ClampedArray() without new throws |
7 | 14 | 44 | No | 15 | 5.1 |
Mobile | ||||||
---|---|---|---|---|---|---|
Uint8ClampedArray() constructor |
4 | 18 | 4 | 12 | 4.2 | 1.0 |
Constructor without arguments | ≤37 | 18 | 55 | 12 | 5 | 1.0 |
new Uint8ClampedArray(iterable) |
39 | 39 | 52 | 26 | 10 | 4.0 |
Uint8ClampedArray() without new throws |
≤37 | 18 | 44 | 14 | 5 | 1.0 |
Server | |
---|---|
Uint8ClampedArray() constructor |
0.10 |
Constructor without arguments | 0.10 |
new Uint8ClampedArray(iterable) |
4.0.0 |
Uint8ClampedArray() without new throws |
0.12 |
Starting with ECMAScript 2015, Uint8ClampedArray
constructors require to be constructed with a new
operator. Calling a Uint8ClampedArray
constructor as a function without new
, will throw a TypeError
from now on.
var dv = Uint8ClampedArray([1, 2, 3]); // TypeError: calling a builtin Uint8ClampedArray constructor // without new is forbidden
var dv = new Uint8ClampedArray([1, 2, 3]);
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https://wiki.developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8ClampedArray/Uint8ClampedArray