This is a 2 min read ยท Published on 07 Sep 2021

I was trying to break Cloudflare Workers tonight and did a search for "CPU intensive JavaScript" because I'm really good at my job.

This gist popped up with the following code:

function mySlowFunction(baseNumber) {
  let result = 0
  for (var i = Math.pow(baseNumber, 7); i >= 0; i--) {
    result += Math.atan(i) * Math.tan(i)

mySlowFunction(8) // higher number => more iterations => slower

Cool, cool. It's some loop that does something and returns a... wait a minute what the heck is Math.atan!?

According to MDN it's:

The Math.atan() function returns the arctangent (in radians) of a number

I don't know anything about math so I'm not even going to pretend to understand actangents but it led me to wondering what other math methods I never heard of. Here's a list:

  • Math.acos(): The Math.acos() function returns the arccosine (in radians) of a number.
  • Math.acosh(): The Math.acosh() function returns the hyperbolic arc-cosine of a number.
  • Math.asin(): The Math.asin() function returns the arcsine (in radians) of a number.
  • Math.asinh(): The Math.asinh() function returns the hyperbolic arcsine of a number.
  • Math.atan2(): The Math.atan2() function returns the angle in the plane (in radians) between the positive x-axis and the ray from (0,0) to the point (x,y), for Math.atan2(y,x).
  • Math.atanh(): The Math.atanh() function returns the hyperbolic arctangent of a number.
  • Math.cbrt(): The Math.cbrt() function returns the cube root of a number.
  • Math.clz32(): The Math.clz32() function returns the number of leading zero bits in the 32-bit binary representation of a number.
  • Math.cosh(): The Math.cosh() function returns the hyperbolic cosine of a number, that can be expressed using the constant e.
  • Math.expm1(): The Math.expm1() function returns e^x - 1, where x is the argument, and e the base of the natural logarithms.
  • Math.fround(): The Math.fround() function returns the nearest 32-bit single precision float representation of a Number.
  • Math.hypot(): The Math.hypot() function returns the square root of the sum of squares of its arguments.
  • Math.imul(): The Math.imul() function returns the result of the C-like 32-bit multiplication of the two parameters.
  • Math.log10(): The Math.log10() function returns the base 10 logarithm of a number.
  • Math.log1p(): The Math.log1p() function returns the natural logarithm (base e) of 1 + a number.
  • Math.log2(): The Math.log2() function returns the base 2 logarithm of a number.
  • Math.sin(): The Math.sin() function returns the sine of a number.
  • Math.sinh(): The Math.sinh() function returns the hyperbolic sine of a number, that can be expressed using the constant e.
  • Math.tan(): The Math.tan() function returns the tangent of a number.
  • Math.tanh(): The Math.tanh() function returns the hyperbolic tangent of a number.
  • Math.trunc(): The Math.trunc() function returns the integer part of a number by removing any fractional digits.

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