Create a hexadecimal colour based on a string with JavaScript

Question

I want to create a function that will accept any old string (will usually be a single word) and from that somehow generate a hexadecimal value between #000000

Answer 1

Using the hashCode as in Cristian Sanchez's answer with hsl and modern javascript, you can create a color picker with good contrast like this:

function hashCode(str) {
  let hash = 0;
  for (var i = 0; i < str.length; i++) {
    hash = str.charCodeAt(i) + ((hash << 5) - hash);
  }
  return hash;
}

function pickColor(str) {
  return `hsl(${hashCode(str) % 360}, 100%, 80%)`;
}

one.style.backgroundColor = pickColor(one.innerText)
two.style.backgroundColor = pickColor(two.innerText)

div {
  padding: 10px;
}

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Two

Since it's hsl, you can scale luminance to get the contrast you're looking for.

function hashCode(str) {
  let hash = 0;
  for (var i = 0; i < str.length; i++) {
    hash = str.charCodeAt(i) + ((hash << 5) - hash);
  }
  return hash;
}

function pickColor(str) {
  // Note the last value here is now 50% instead of 80%
  return `hsl(${hashCode(str) % 360}, 100%, 50%)`;
}

one.style.backgroundColor = pickColor(one.innerText)
two.style.backgroundColor = pickColor(two.innerText)

div {
  color: white;
  padding: 10px;
}

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