Math.clz32()

Summary

The Math.clz32() function returns the number of leading zero bits in the 32-bit binary representation of a number.

Syntax

Math.clz32 (x)

Parameters

x

A number.

Description

"clz32" is short for CountLeadingZeroes32.

If x is not a number, then it will be converted to a number first, then converted to a 32-bit unsigned integer. 

If the converted 32-bit unsigned integer is 0, then return 32, because all bits are 0.

This function is particularly useful for systems that compile to JS, like Emscripten.

Examples

Math.clz32(1)                // 31
Math.clz32(1000)             // 22 
Math.clz32()                 // 32

[NaN, Infinity, -Infinity, 0, -0, null, undefined, "foo", {}, []].filter(
function (n) {
  return Math.clz32(n) !== 32
})                           // []

Math.clz32(true)             // 31
Math.clz32(3.5)              // 30

Polyfill

Math.clz32 = Math.clz32 || function(value) {
    var value = Number(value) >>> 0;
    return value ? 32 - value.toString(2).length : 32;
}

Specifications

Browser compatibility

See also

• Math