Convert a base64 string into a binary Uint8 Array

gistfile1.js

var BASE64_MARKER = ';base64,';

function convertDataURIToBinary(dataURI) {
  var base64Index = dataURI.indexOf(BASE64_MARKER) + BASE64_MARKER.length;
  var base64 = dataURI.substring(base64Index);
  var raw = window.atob(base64);
  var rawLength = raw.length;
  var array = new Uint8Array(new ArrayBuffer(rawLength));

  for(i = 0; i < rawLength; i++) {
    array[i] = raw.charCodeAt(i);
  }
  return array;
}

One liner to convert Base64 to Uint8Array:

function Uint8ArrayFromBase64(base64)
{
    return Uint8Array.from(window.atob(base64), (v) => v.charCodeAt(0));
}

One liner to convert Base64Url to Uint8Array:

function Uint8ArrayFromBase64Url(base64Url)
{
    return Uint8Array.from(window.atob(base64Url.replace(/-/g, "+").replace(/_/g, "/")), (v) => v.charCodeAt(0));
}

ERROR: Uncaught DOMException: Failed to execute 'atob' on 'Window': The string to be decoded is not correctly encoded
I am running it with typescript react. Any idea?

Thanks for this! The only solution that worked for me @borismus

How to convert this recordfile:///var/mobile/Containers/Data/Application/9C0F0870-EA7F-4CD2-9C42-30A3E9862012/Library/Caches/hello.m4a into binary format.

Thank you so much sir, very respects <3

Thank you very much for this, after a week of pulling my hair out. This is the only solution that works for me.

Thank you very much, you save my work

Thank you, good work !

Thank you man! you save my day!

Thanks buddy, save my day!

It can be even shorter (1 line): https://gist.github.com/av01d/e60f6edf3c5be6cd403eabb3d1f838f4

A note on the one-liners: While Uint8Array.from(atob(base64), (v) => v.charCodeAt(0)); really looks nice, I ran into memory issues on Chrome when converting a 200MB binary while the for-loop worked flawlessly

Uncaught DOMException: String contains an invalid character
convertDataURIToBinary debugger eval code:6
downloadFile debugger eval code:17
debugger eval code:1