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).
Syntax
new Uint8ClampedArray(); // new in ES2017
new Uint8ClampedArray(length);
new Uint8ClampedArray(typedArray);
new Uint8ClampedArray(object);
new Uint8ClampedArray(buffer [, byteOffset [, length]]);
Parameters
length
- When called with a
length
argument, an internal array buffer is created in memory, of sizelength
multiplied byBYTES_PER_ELEMENT
bytes, containing zeros. typedArray
- When called with a
typedArray
argument, which can be an object of any of the typed array types (such asInt32Array
), thetypedArray
gets copied into a new typed array. Each value intypedArray
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 thetypedArray
argument. object
- When called with an
object
argument, a new typed array is created as if by theTypedArray.from()
method. buffer
,byteOffset
,length
- When called with a
buffer
, and optionally abyteOffset
and alength
argument, a new typed array view is created that views the specifiedArrayBuffer
. ThebyteOffset
andlength
parameters specify the memory range that will be exposed by the typed array view. If both are omitted, all ofbuffer
is viewed; if onlylength
is omitted, the remainder ofbuffer
is viewed.
Examples
Different ways to create a Uint8ClampedArray
// 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]
Specifications
Specification |
---|
ECMAScript (ECMA-262) The definition of 'TypedArray constructors' in that specification. |
Browser compatibility
BCD tables only load in the browser
Compatibility notes
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]);