Uint8Array.fromHex()

The Uint8Array.fromHex() static method creates a new Uint8Array object from a hexadecimal string.

This method parses the string into a byte array. To convert the string into a single number, use the parseInt() function with radix set to 16 instead.

Syntax

Uint8Array.fromHex(string)

Parameters

string

A hexadecimal string encoding bytes to convert to a Uint8Array. The string must:

Have an even number of characters because two characters encode one byte.
Only contain characters in the hexadecimal alphabet, which includes 0–9 and A–F (case-insensitive).
Not contain whitespace (unlike Uint8Array.prototype.setFromBase64()).

Return value

A new Uint8Array object containing the decoded bytes from the hexadecimal string.

Exceptions

SyntaxError: Thrown if the input string contains characters outside the hex alphabet, or its length is odd.
TypeError: Thrown if the input string is not a string.

Examples

undefined

Decoding a hexadecimal string

This example decodes a hexadecimal string into a Uint8Array.

const hexString = "cafed00d";
const bytes = Uint8Array.fromHex(hexString);
console.log(bytes); // Uint8Array [ 202, 254, 208, 13 ]

Uppercase characters are also supported:

const hexString = "CAFEd00d";
const bytes = Uint8Array.fromHex(hexString);
console.log(bytes); // Uint8Array [ 202, 254, 208, 13 ]

Specifications

ECMAScript® 2027 Language Specification