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Discussion on: Write a script to find "Happy Numbers"

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Replies for: Your code in ES2016+ (and a bit less readable): const isHappy = n => { if (n === 4) return false; const u = [...n.toString()].reduce((ac...

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Nick Taylor •

You could even shorten the toString by replacing it with a template string which will do an implicit toString.

const isHappy = n => {
  if (n === 4) return false;

  const u = [...`${n}`].reduce((ac, c) => ac + (c ** 2), 0);

  return u === 1 || isHappy(u);
};