Benchmark: Convert binary string to bytes

Convert binary string to bytes (version: 2)

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).

Comparing performance of: `Uint8Array.from + codePointAt vs Uint8Array.from + charCodeAt vs for-loop + codePointAt vs for-loop + charCodeAt vs for-loop + Uint8Array.from + codePointAt (small chunk) vs for-loop + Uint8Array.from + charCodeAt (small chunk) vs for-loop + Uint8Array.from + codePointAt (big chunk) vs for-loop + Uint8Array.from + charCodeAt (big chunk)`

Created: one year ago by: Registered User

Go to the latest result

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;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
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)

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/133.0.0.0 Safari/537.36

Browser/OS: Chrome 133 on Windows

View result in a separate tab

Uint8Array.from + charCodeAt

13/s

Uint8Array.from + codePointAt

12/s

for-loop + codePointAt

10/s

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

9/s

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

9/s

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

9/s

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

9/s

for-loop + charCodeAt

9/s

View exact numbers

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