Run results for: Convert binary string to bytes

Test name	Executions per second
✓ Uint8Array.from + charCodeAt	13 Ops/sec
Uint8Array.from + codePointAt	12 Ops/sec
for-loop + codePointAt	10 Ops/sec
for-loop + Uint8Array.from + codePointAt (big chunk)	9 Ops/sec
for-loop + Uint8Array.from + charCodeAt (big chunk)	9 Ops/sec
for-loop + Uint8Array.from + charCodeAt (small chunk)	9 Ops/sec
for-loop + Uint8Array.from + codePointAt (small chunk)	9 Ops/sec
for-loop + charCodeAt	9 Ops/sec

Script Preparation code:

function get1024Bytes(n) {
  const bytes = new Uint8Array(n * 1024);
  for (let i = 0; i < bytes.length; i += 1) {
    bytes[i] = Math.random() * 0xff;
  }
  return bytes;
}

const bytes = get1024Bytes(1024);

/*
   Note that Function.prototype.apply() has a limit, so not using it to creat binary string here for convenience.
   
   To use it, split the array into smaller chunks first.
   
       String.fromCodePoint.apply(null, bytes);  // bytes.length should not exceed the maximum

   See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/apply
*/

const binString = Array.from(bytes, (byte) => String.fromCodePoint(byte)).join("");

Tests:

Uint8Array.from + codePointAt
return Uint8Array.from(binString, (m) => m.codePointAt(0));
Uint8Array.from + charCodeAt
return Uint8Array.from(binString, (m) => m.charCodeAt(0));
for-loop + codePointAt
const bytes = new Uint8Array(binString.length); for (let i = 0; i < bytes.length; i += 1) { bytes[i] = binString[i].codePointAt(0); } return bytes;
for-loop + charCodeAt
const bytes = new Uint8Array(binString.length); for (let i = 0; i < bytes.length; i += 1) { bytes[i] = binString[i].charCodeAt(0); } return bytes;
for-loop + Uint8Array.from + codePointAt (small chunk)
const QUANTUM = 128; const bytes = new Uint8Array(binString.length); for (let i = 0; i < binString.length; i += QUANTUM) { let j = i; for (const b of Uint8Array.from(binString.slice(i, i + QUANTUM), (m) => m.codePointAt(0))) { bytes[j] = b; j += 1; } } return bytes;
for-loop + Uint8Array.from + charCodeAt (small chunk)
const QUANTUM = 128; const bytes = new Uint8Array(binString.length); for (let i = 0; i < binString.length; i += QUANTUM) { let j = i; for (const b of Uint8Array.from(binString.slice(i, i + QUANTUM), (m) => m.charCodeAt(0))) { bytes[j] = b; j += 1; } } return bytes;
for-loop + Uint8Array.from + codePointAt (big chunk)
const QUANTUM = 32768; const bytes = new Uint8Array(binString.length); for (let i = 0; i < binString.length; i += QUANTUM) { let j = i; for (const b of Uint8Array.from(binString.slice(i, i + QUANTUM), (m) => m.codePointAt(0))) { bytes[j] = b; j += 1; } } return bytes;
for-loop + Uint8Array.from + charCodeAt (big chunk)
const QUANTUM = 32768; const bytes = new Uint8Array(binString.length); for (let i = 0; i < binString.length; i += QUANTUM) { let j = i; for (const b of Uint8Array.from(binString.slice(i, i + QUANTUM), (m) => m.charCodeAt(0))) { bytes[j] = b; j += 1; } } return bytes;

Run results for: Convert binary string to bytes

To use browser's atob() or btoa(), we need to convert between bytes and so-called "binary" string. This test converts "binary" string to bytes, for working with results from atob() calls, which decodes base64 to bytes (in the form of binary string).

Uint8Array.from + codePointAt

Uint8Array.from + charCodeAt

for-loop + codePointAt

for-loop + charCodeAt

for-loop + Uint8Array.from + codePointAt (small chunk)

for-loop + Uint8Array.from + charCodeAt (small chunk)

for-loop + Uint8Array.from + codePointAt (big chunk)

for-loop + Uint8Array.from + charCodeAt (big chunk)