Javascript trailing zero bits

javascript-trailing-zero-bits.js

class Bitwise {
  static trailingZeros8(b) {
    let lsb = (b & -b)
    if(lsb === 0) { return 8 }
    return 31 - Math.clz32(lsb)
  }
  static trailingZeros64(a) {
    for(let i=7; i>=0; i--) {
      let z = Bitwise.trailingZeros8(a[i])
      if(z < 8) { return ((7-i) * 8) + z }
    }
    return 64
  }
  static trailingZeros(a) {
    let t = a.length-1
    for(let i=t; i>=0; i--) {
      let z = Bitwise.trailingZeros8(a[i])
      if(z < 8) { return ((t-i) * 8) + z }
    }
    return a.length * 8
  }
}

Bitwise.trailingZeros64([0xff, 0xff, 0xff, 0xff, 0xf0, 0x00, 0x00, 0x00])