How can I specify the base for Math.log() in JavaScript?

Question

I need a log function for JavaScript, but it needs to be base 10. I can\'t see any listing for this, so I\'m assuming it\'s not possible. Are there any math wiz

Answer 1

Math.log10(x)!

Answer 2

the answer here would cause obvious precision problem and is not reliable in some use cases

> Math.log(10)/Math.LN10
1

> Math.log(100)/Math.LN10
2

> Math.log(1000)/Math.LN10
2.9999999999999996

> Math.log(10000)/Math.LN10
4

Answer 3

const logBase = (n, base) => Math.log(n) / Math.log(base);

https://en.wikipedia.org/wiki/Logarithm#Change_of_base

Answer 4

"Change of Base" Formula / Identity

The numerical value for logarithm to the base 10 can be calculated with the following identity.

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Since Math.log(x) in JavaScript returns the natural logarithm of x (same as ln(x)), for base 10 you can divide by Math.log(10) (same as ln(10)):

function log10(val) {
  return Math.log(val) / Math.LN10;
}

Math.LN10 is a built-in precomputed constant for Math.log(10), so this function is essentially identical to:

function log10(val) {
  return Math.log(val) / Math.log(10);
}