Taken from DailyCodingProblem

Implement integer exponentiation. That is, implement the pow(x, y) function, where x and y are integers and returns x^y.

Do this faster than the native method of repeated multiplication.

Solution

This is the answer I came up with:

const exponent = (x: number, y: number): number => x ** y

const custom = (x: number, y: number): number => {
  let result = x
  for (let _ = 1; _ < y; _++) {
    result *= x
  }
  return result
}

Both functions handle exponentiation: the exponent function does it using the exponential operator, and the custom function implements it arithmetically. The custom function is probably the more correct answer, but both functions are faster when tested against the native Math.pow() method.

Testing

Solution tested in REPL:

https://www.typescriptlang.org/play?#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-Nq94e1Dx7HMSiYLiO4ou6mYOmkX2lAPi+vS0jM+PTjXh2PmzB53Ql0nECm6wAWbHjndDvdIg9Hye1t+92dtujIsuq6ns+mhFq+G5lp+ZzDgAbH+8ZQkBt7dj+T79mBg5Rm+H75seU44fe45KHYhIuGoMBLPAKRJL4ODwL8-zfIxAJAtQPAnPAsSxOQ8DAAA1kQ8BgHIkSZAs7poJ6SBLDgKrcbxAkiAgSwKG07hcTxfH8fRLGbGidAMX89CbCU5xqTEEkel6aAAKJgKscmaYp-HKUGaBqbMSg5HkCywGIbxWCAWQwHcUCPC8gUQM0rSWW6HqxCADw4AF7wWZRyxrBAIg+bZfFCDgSxQCsVqYHwVE0WgKWBXQRUlWwnlXIShIwAAStQ3KheMSToB8GDKqqEAYJIDGkMQYiEiqwBCGghIJMA3m5LgfkwKlQUhWFEVUK87zZT11BDTgDUtOJ8VSYlyVreldVZTluR5dNhWZaV5VoNRoxVWttXPQ1MxKEAA