James Garbutt

Software engineer. Front-end @crispthinking. JavaScript & HTML5 expert.

Using the new Math methods in ES6

July 24, 2014

Edit Page

Canary releases are getting better and better each time. This time, we see the introduction of several useful Math functions implemented according to the ES6 specification.

I spend quite a large chunk of time working on mathematical applications so these are a very nice addition for those of you in similar shoes.

clz32

clz32 (Count Leading Zeroes 32) does what it says on the tin, it counts all leading zeroes in the 32-bit representation of the provided int.

The easiest way to show this is using the binary notation of a 32-bit integer like follows:

0b1000000;
// 64

Math.clz32(0b1000000);
// 25 (32 minus 7 digits)

hypot

As the name says, hypot calculates the hypotenuse (yay pythagoras!), the usual sqrt(a^2 + b^2) but with the ability to provide any number of arguments like so:

Math.hypot(a, b, c);
// sqrt(a^2 + b^2 + c^2)

trunc

Native truncation functionality. This would be calculated by using ceil when the value is less than zero and floor greater than or equal to zero. However, now it is as simple as:

Math.trunc(3.1415927);
// 3

sign

A very handy function to get the sign of a value, useful in a bunch of places:

Math.sign(10);
// 1

Math.sign(-10);
// -1

Math.sign(0);
// 0

Math.sign(-0);
// -0

Math.sign(NaN);
// NaN

Math.sign(Infinity);
// 0

As you can see:

  • 1 is positive
  • -1 is negative
  • 0 is positive zero
  • -0 is negative zero
  • NaN is NaN

A few more

This release also sees the introduction of these handy functions:

  • log10 to calculate the base 10 logarithm
  • log2 to calculate the base 2 logarithm
  • log1p to calculate the natural logarithm
  • expm1 to calculate exp(x) - 1
  • imul for 32-bit multiplication
  • fround to round a number to single precision
  • cbrt to perform a cube root