Determine whether a JavaScript value is a power of two (non-broken edition)

isPowerOfTwo.js

// Exports a function which determines whether a JavaScript value is a power of
// two or not. Unlike the npm package `is-power-of-two`, this actually returns
// the correct answer in all cases.

const powersOfTwo = new Set()
for (let i = Number.MIN_VALUE; i <= Number.MAX_VALUE; i *= 2) {
  powersOfTwo.add(i)
}

export default x => powersOfTwo.has(x)