How to convert text to binary code in JavaScript?

Question

Text to Binary Code

I want JavaScript to translate text in a textarea into binary code.

For example, if a user types in "TEST

Answer 1

Provided you're working in node or a browser with BigInt support, this version cuts costs by saving the expensive string construction for the very end:

const zero = 0n
const shift = 8n

function asciiToBinary (str) {
  const len = str.length
  let n = zero
  for (let i = 0; i < len; i++) {
    n = (n << shift) + BigInt(str.charCodeAt(i))
  }
  return n.toString(2).padStart(len * 8, 0)
}

It's about twice as fast as the other solutions mentioned here including this simple es6+ implementation:

const toBinary = s => [...s]
  .map(x => x
    .codePointAt()
    .toString(2)
    .padStart(8,0)
  )
  .join('')

If you need to handle unicode characters, here's this guy:

const zero = 0n
const shift = 8n
const bigShift = 16n
const byte = 255n

function unicodeToBinary (str) {
  const len = str.length
  let n = zero
  for (let i = 0; i < len; i++) {
    const bits = BigInt(str.codePointAt(i))
    n = (n << (bits > byte ? bigShift : shift)) + bits
  }
  const bin = n.toString(2)
  return bin.padStart(8 * Math.ceil(bin.length / 8), 0)
}