lib0/number.js

> Monorepo of isomorphic utility functions

/**
 * Utility helpers for working with numbers.
 *
 * @module number
 */

import * as math from './math.js'
import * as binary from './binary.js'

export const MAX_SAFE_INTEGER = Number.MAX_SAFE_INTEGER
export const MIN_SAFE_INTEGER = Number.MIN_SAFE_INTEGER

export const LOWEST_INT32 = 1 << 31
export const HIGHEST_INT32 = binary.BITS31
export const HIGHEST_UINT32 = binary.BITS32

/* c8 ignore next */
export const isInteger = Number.isInteger || (num => typeof num === 'number' && isFinite(num) && math.floor(num) === num)
export const isNaN = Number.isNaN
export const parseInt = Number.parseInt

/**
 * Count the number of "1" bits in an unsigned 32bit number.
 *
 * Super fun bitcount algorithm by Brian Kernighan.
 *
 * @param {number} n
 */
export const countBits = n => {
  n &= binary.BITS32
  let count = 0
  while (n) {
    n &= (n - 1)
    count++
  }
  return count
}