Efficient way to convert base64 string to ArrayBuffer

Given a base64 string, what is the safest and most efficient way to create an ArrayBuffer. Specifically a typeless array buffer in pure modern JavaScript.

The first SO result is this question from 2014. The accepted answer is

function _base64ToArrayBuffer(base64) {
    var binary_string = window.atob(base64);
    var len = binary_string.length;
    var bytes = new Uint8Array(len);
    for (var i = 0; i < len; i++) {
        bytes[i] = binary_string.charCodeAt(i);
    return bytes.buffer;

It already assumes a type and there are comments which suggest that this is not always correct.

Is this still the best solution today? Do we have to iterate over all elements in a for loop? Is there a better and more efficient way using vanilla JS where we can pass a blob of the string?

An example problem is processing a GLTF buffer which is provided as a base64 encoded string:


This has two separate views of scalar (unsigned short) and vec3 (float) data, requiring further processing.

Source: JavaSript – Stack Overflow

November 13, 2021
Category : News
Tags: arraybuffer | base64 | javascript

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Senior Software Developer

Creator of @LzoMedia I am a backend software developer based in London who likes beautiful code and has an adherence to standards & love's open-source.