TypedArray

Baseline

20157

TypedArray TypedArray TypedArray

TypedArray %TypedArray% JavaScript TypedArray %TypedArray% TypedArray Object.getPrototypeOf(Int8Array)

TypedArray Int8Array ArrayBuffer ArrayBuffer %TypedArray%.prototype

TypedArray

		()	Web IDL
`Int8Array`	-128 127	1	`byte`
`Uint8Array`	0 255	1	`octet`
`Uint8ClampedArray`	0 255	1	`octet`
`Int16Array`	-32768 32767	2	`short`
`Uint16Array`	0 65535	2	`unsigned short`
`Int32Array`	-2147483648 2147483647	4	`long`
`Uint32Array`	0 4294967295	4	`unsigned long`
`Float16Array`	`-65504` `65504`	2
`Float32Array`	`-3.4E38` `3.4E38` `1.2E-38`	4	`unrestricted float`
`Float64Array`	`-1.8E308` `1.8E308` `5E-324`	8	`unrestricted double`
`BigInt64Array`	-263 to 263 - 1	8	`bigint`
`BigUint64Array`	0 to 264 - 1	8	`bigint`

ArrayBuffer

(Uint8Array, Uint16Array, Uint32Array, BigUint64Array)
(Int8Array, Int16Array, Int32Array, BigInt64Array) 2
(Float16Array, Float32Array, Float64Array) IEEE 754 Number JavaScript Float64Array Float32Array 52 23 11 8 Float16Array 10 5 NaN
Uint8ClampedArray Uint8Array 0 255

Int8ArrayUint8ArrayUint8ClampedArray DataView

Uint8ClampedArray
Uint8ClampedArray 0 255 255 255 0 0 2 0.5 01.5 22.5 2
Float16Array Float32Array "round to even" 64 32 16 Math.fround() Math.f16round()

TypedArray TypedArray TypedArray

3undefined buffer

const buffer = new ArrayBuffer(8, { maxByteLength: 16 });
const float32 = new Float32Array(buffer);

console.log(float32.byteLength); // 8
console.log(float32.length); // 2

buffer.resize(12);

console.log(float32.byteLength); // 12
console.log(float32.length); // 3

3 length buffer

const buffer = new ArrayBuffer(8, { maxByteLength: 16 });
const float32 = new Float32Array(buffer, 0, 2);

console.log(float32.byteLength); // 8
console.log(float32.length); // 2
console.log(float32[0]); // 0

buffer.resize(12);

console.log(float32.byteLength); // 8
console.log(float32.length); // 2
console.log(float32[0]); // 0

buffer 0

const buffer = new ArrayBuffer(8, { maxByteLength: 16 });
const float32 = new Float32Array(buffer, 0, 2);

buffer.resize(7);

console.log(float32.byteLength); // 0
console.log(float32.length); // 0
console.log(float32[0]); // undefined

buffer

buffer.resize(8);

console.log(float32.byteLength); // 8
console.log(float32.length); // 2
console.log(float32[0]); // 0 - back in bounds again!

byteOffset

const buffer = new ArrayBuffer(8, { maxByteLength: 16 });
const float32 = new Float32Array(buffer, 4);
// float32 4 
//  4 
// 
buffer.resize(3);
console.log(float32.byteLength); // 0

new TypeError

new (Object.getPrototypeOf(Int8Array))();
// TypeError: Abstract class TypedArray not directly constructable

Int8Array BigInt64Array

new TypedArray()
new TypedArray(length)
new TypedArray(typedArray)
new TypedArray(object)

new TypedArray(buffer)
new TypedArray(buffer, byteOffset)
new TypedArray(buffer, byteOffset, length)

TypedArray

: TypedArray new new TypeError

typedArray: TypedArray typedArray TypedArray typedArray Int32Array TypedArray BigInt64Array BigUint64ArraytypedArray typedArray typedArray
object: TypedArray TypedArray.from()
length: length BYTES_PER_ELEMENT 0 0 length
buffer, byteOffset , length: ArrayBuffer SharedArrayBuffer byteOffset length byteOffset length BYTES_PER_ELEMENT buffer length buffer byteOffset length

TypeArray

TypeError

typedArray
typedArray buffer

RangeError

buffer length byteOffset
byteOffset 0 253 - 1
byteOffset + length * TypedArray.BYTES_PER_ELEMENT > buffer.byteLength

TypedArray TypedArray

TypedArray[Symbol.species]

TypedArray

TypedArray.BYTES_PER_ELEMENT: TypedArray

TypedArray TypedArray

TypedArray.from(): TypedArray Array.from()
TypedArray.of(): TypedArray Array.of()

TypedArray.prototype TypedArray

TypedArray.prototype.buffer: ArrayBuffer
TypedArray.prototype.byteLength: ()
TypedArray.prototype.byteOffset: ArrayBuffer ()
TypedArray.prototype.constructor: TypedArray.prototype.constructor TypedArray constructor
TypedArray.prototype.length
TypedArray.prototype[Symbol.toStringTag]: TypedArray.prototype[Symbol.toStringTag] this undefined Object.prototype.toString() TypedArray toString() Object.prototype.toString.call() thisArg

TypedArray

TypedArray.prototype.BYTES_PER_ELEMENT: TypedArray

TypedArray TypedArray

TypedArray.prototype.at()
TypedArray.prototype.copyWithin(): Array.prototype.copyWithin()
TypedArray.prototype.entries(): Array.prototype.entries()
TypedArray.prototype.every(): 1 false true Array.prototype.every()
TypedArray.prototype.fill(): Array.prototype.fill()
TypedArray.prototype.filter(): true Array.prototype.filter()
TypedArray.prototype.find(): undefined Array.prototype.find()
TypedArray.prototype.findIndex(): -1 Array.prototype.findIndex()
TypedArray.prototype.findLast(): undefined Array.prototype.findLast()
TypedArray.prototype.findLastIndex(): -1 Array.prototype.findLastIndex()
TypedArray.prototype.forEach(): Array.prototype.forEach()
TypedArray.prototype.includes(): true false Array.prototype.includes()
TypedArray.prototype.indexOf(): -1 Array.prototype.indexOf()
TypedArray.prototype.join(): 1 Array.prototype.join()
TypedArray.prototype.keys(): Array.prototype.keys()
TypedArray.prototype.lastIndexOf(): -1 Array.prototype.lastIndexOf()
TypedArray.prototype.map(): Array.prototype.map()
TypedArray.prototype.reduce(): Array.prototype.reduce()
TypedArray.prototype.reduceRight(): Array.prototype.reduce()
TypedArray.prototype.reverse(): Array.prototype.reverse()
TypedArray.prototype.set()
TypedArray.prototype.slice(): Array.prototype.slice()
TypedArray.prototype.some(): 1 true false Array.prototype.some()
TypedArray.prototype.sort(): Array.prototype.sort()
TypedArray.prototype.subarray(): TypedArray
TypedArray.prototype.toLocaleString(): Array.prototype.toLocaleString()
TypedArray.prototype.toReversed()
TypedArray.prototype.toSorted()
TypedArray.prototype.toString(): Array.prototype.toString()
TypedArray.prototype.values(): Array.prototype.values()
TypedArray.prototype.with()
TypedArray.prototype[Symbol.iterator]()

() ArrayBuffer

// 
const int16 = new Int16Array(2);
int16[0] = 42;
console.log(int16[0]); // 42

//  (Fx 25)
Int8Array.prototype[20] = "foo";
new Int8Array(32)[20]; // 0
// even when out of bound
Int8Array.prototype[20] = "foo";
new Int8Array(8)[20]; // undefined
// or with negative integers
Int8Array.prototype[-1] = "foo";
new Int8Array(8)[-1]; // undefined

//  (Fx 30)
Int8Array.prototype.foo = "bar";
new Int8Array(32).foo; // "bar"

TypedArray ArrayBuffer TypedArray

const i8 = Int8Array.of(1, 2, 3);
Object.freeze(i8);
// TypeError: Cannot freeze array buffer views with elements

ByteOffset

ArrayBuffer TypedArray byteOffset BYTES_PER_ELEMENT

const i32 = new Int32Array(new ArrayBuffer(4), 1);
// RangeError: start offset of Int32Array should be a multiple of 4

const i32 = new Int32Array(new ArrayBuffer(4), 0);

ByteLength

byteOffset TypedArray ArrayBuffer byteLength BYTES_PER_ELEMENT

const i32 = new Int32Array(new ArrayBuffer(3));
// RangeError: byte length of Int32Array should be a multiple of 4

const i32 = new Int32Array(new ArrayBuffer(4));


ECMAScript 2027 LanguageSpecification # sec-typedarray-objects

MDN

MDN 2026122

GitHub