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13 August 20265 min readUpdated 13 August 2026

Understanding JavaScript Typed Arrays

JavaScript Typed Arrays Overview of Typed Arrays Typed arrays in JavaScript are designed specifically for handling binary data. Unlike regular arrays, these arrays are buffers w...

Understanding JavaScript Typed Arrays

JavaScript Typed Arrays

Overview of Typed Arrays

Typed arrays in JavaScript are designed specifically for handling binary data. Unlike regular arrays, these arrays are buffers with a fixed length and store elements of specific data types, such as 8-bit integers or 32-bit numbers.

Advantages of Typed Arrays

Typed arrays offer an efficient method for managing binary data compared to traditional JavaScript arrays, which can contain elements of various types. As raw memory, typed arrays can be directly passed to functions without data conversion. They are much faster for functions that process raw binary data, making them ideal for:

  • WebGL and Canvas: Fast graphics rendering and image processing.
  • File APIs: Efficient reading and writing of local files.
  • Media APIs: Swift handling of audio and video data.
  • WebSockets: Effective binary data transfer over networks.

Typed arrays handle binary data as efficiently as arrays in languages like C.

Browser APIs Supporting Typed Arrays

Typed arrays are supported by various browser APIs, enhancing their utility in web development environments.

Differences from Regular Arrays

  • Fixed Length: Typed arrays cannot be resized dynamically using methods such as push() or pop().
  • Type Restriction: Elements must conform to the specified data type of the typed array.
  • Underlying Buffer: Typed arrays are views into an ArrayBuffer, enabling direct manipulation of binary data.

Types of Typed Arrays

| Name | Min | Max | Bytes | Type | |--------------------|--------------|---------------|-------|-------------------| | 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 | | BigInt64Array | -2^63 | 2^63 - 1 | 8 | bigint | | BigUint64Array | 0 | 2^64 - 1 | 8 | unsigned bigint | | Float16Array | -65504 | 65504 | 2 | unrestricted half | | Float32Array | -3.4e38 | 3.4e38 | 4 | unrestricted float| | Float64Array | -1.8e308 | 1.8e308 | 8 | unrestricted double|

Illustration for: | Name | Min ...

8-Bit Integers

| Name | Data Type | Range | |-------------------|-------------------------|-----------| | Int8Array | Signed integer (byte) | -128/127 | | Uint8Array | Unsigned integer (octet)| 0/255 | | Uint8ClampedArray| Unsigned integer (octet)| 0/255 |

Uint8Array vs Uint8ClampedArray

The primary difference between Uint8Array and Uint8ClampedArray is how they handle values outside the 0-255 range. In Uint8ClampedArray, values are clamped to 0 or 255, whereas a Uint8Array simply uses the first 8 bits of the value.

Typed arrays are not regular arrays. For instance, isArray() returns false for typed arrays, and many standard array methods like push and pop are not supported.

16-Bit Integers

| Name | Data Type | Range | |--------------|--------------------|-------------| | Int16Array | Short integer | -32768/32767| | Uint16Array| Unsigned short int | 0/65535 |

32-Bit Integers

| Name | Data Type | Range | |--------------|-------------------|-----------------------| | Int32Array | Signed long int | -2147483648/2147483647| | Uint32Array| Unsigned long int | 0/4294967295 |

64-Bit Integers

| Name | Data Type | Range | |-----------------|-------------------|-------------| | BigInt64Array | Big signed int | -2^63/2^63-1| | BigUint64Array| Big unsigned int | 0/2^64 |

Floating Point Numbers

| Name | Description | Range | |---------------|----------------------------------------|----------------------| | Float16Array| Half precision - 3 significant digits | -65504 / 65504 | | Float32Array| Normal precision - 7 significant digits| -3.4e38 / 3.4e38 | | Float64Array| Double precision - 15 significant digits| -1.8e308 / 1.8e308 |

In line with the ECMAScript standard, arithmetic in JavaScript uses double-precision floating-point arithmetic.

Browser Compatibility

Typed arrays are a feature of ES6 and are supported by all modern browsers since mid-2017, including Chrome, Edge, Firefox, Safari, and Opera.