TypedArray

20157

TypedArray TypedArray TypedArray

// Create a TypedArray with a size in bytes
const typedArray1 = new Int8Array(8);
typedArray1[0] = 32;

const typedArray2 = new Int8Array(typedArray1);
typedArray2[1] = 42;

console.log(typedArray1);
// Expected output: Int8Array [32, 0, 0, 0, 0, 0, 0, 0]

console.log(typedArray2);
// Expected output: Int8Array [32, 42, 0, 0, 0, 0, 0, 0]

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

TypedArray Int8Array ArrayBuffer ArrayBuffer %TypedArray%.prototype

TypedArray

				Web IDL	C
`Int8Array`	-128 127	1	8	`byte`	`int8_t`
`Uint8Array`	0 255	1	8	`octet`	`uint8_t`
`Uint8ClampedArray`	0 255	1	8 0 255	`octet`	`uint8_t`
`Int16Array`	-32768 32767	2	16	`short`	`int16_t`
`Uint16Array`	0 65535	2	16	`unsigned short`	`uint16_t`
`Int32Array`	-2147483648 2147483647	4	32	`long`	`int32_t`
`Uint32Array`	0 4294967295	4	32	`unsigned long`	`uint32_t`
`Float32Array`	`-3.4E38` `3.4E38` `1.2E-38`	4	32 IEEE 7 `1.234567`	`unrestricted float`	`float`
`Float64Array`	`-1.8E308` `1.8E308` `5E-324`	8	64 IEEE 16 `1.23456789012345`	`unrestricted double`	`double`
`BigInt64Array`	-263 263 - 1	8	64	`bigint`	`int64_t (signed long long)`
`BigUint64Array`	0 264 - 1	8	64	`bigint`	`uint64_t (unsigned long long)`

ArrayBuffer

Uint8ArrayUint16ArrayUint32Array BigUint64Array
Int8ArrayInt16ArrayInt32Array BigInt64Array
Float32Array Float64Array IEEE 754 Number JavaScript Float64Array Float32Array 23 52 8 11 NaN
Uint8ClampedArray Uint8Array clamp 0 255

Int8ArrayUint8Array Uint8ClampedArray DataView

Uint8ClampedArray
Uint8ClampedArray 0 255 255 255 0 00.5 01.5 22.5 2
Float32Array 64 32 Math.fround()

TypedArray TypedArray TypedArray

undefined 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

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 -

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

TypeArray

TypeError

typedArray bigint
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 getter TypedArray

TypedArray.prototype.buffer: ArrayBuffer
TypedArray.prototype.byteLength
TypedArray.prototype.byteOffset: ArrayBuffer
TypedArray.prototype.length

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(): 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(): 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(): reducer Array.prototype.reduce()
TypedArray.prototype.reduceRight(): reducer Array.prototype.reduceRight()
TypedArray.prototype.reverse(): Array.prototype.reverse()
TypedArray.prototype.set()
TypedArray.prototype.slice(): Array.prototype.slice()
TypedArray.prototype.some(): true Array.prototype.some()
TypedArray.prototype.sort(): Array.prototype.sort()
TypedArray.prototype.subarray(): TypedArray
TypedArray.prototype.values(): Array.prototype.values()
TypedArray.prototype.toLocaleString(): Array.prototype.toLocaleString()
TypedArray.prototype.toString(): Array.prototype.toString()
TypedArray.prototype[Symbol.iterator]()

ArrayBuffer

// Setting and getting using standard array syntax
const int16 = new Int16Array(2);
int16[0] = 42;
console.log(int16[0]); // 42

// Indexed properties on prototypes are not consulted (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

// Named properties are allowed, though (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

TypedArray ArrayBuffer 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 ArrayBuffer TypedArray 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

20251023 MDN

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