How can I round a number in JavaScript? .toFixed() returns a string?

It returns a string because 0.1, and powers thereof (which are used to display decimal fractions), are not representable (at least not with full accuracy) in binary floating-point systems.

For example, 0.1 is really 0.1000000000000000055511151231257827021181583404541015625, and 0.01 is really 0.01000000000000000020816681711721685132943093776702880859375. (Thanks to BigDecimal for proving my point. :-P)

Therefore (absent a decimal floating point or rational number type), outputting it as a string is the only way to get it trimmed to exactly the precision required for display.

Of course it returns a string. If you wanted to round the numeric variable you'd use Math.round() instead. The point of toFixed is to format the number with a fixed number of decimal places for display to the user.

You can simply use a '+' to convert the result to a number.

var x = 22.032423;
x = +x.toFixed(2); // x = 22.03

May be too late to answer but you can multiple the output with 1 to convert to number again, here is an example.

const x1 = 1211.1212121;
const x2 = x1.toFixed(2)*1;
console.log(typeof(x2));

You should use it like below.

var someNumber: number = 0.000000;
someNumber = Number(someNumber.toFixed(2))

Why not * the result by 1 i.e

someNumber.toFixed(2) * 1

What would you expect it to return when it's supposed to format a number ? If you have a number you can't pretty much do anything with it because e.g.2 == 2.0 == 2.00 etc. so it has to be a string.

Because its primary use is displaying numbers? If you want to round numbers, use Math.round() with apropriate factors.

To supply an example of why it has to be a string:

If you format 1.toFixed(2) you would get '1.00'.

This is not the same as 1, as 1 does not have 2 decimals.

I know JavaScript isn't exactly a performance language, but chances are you'd get better performance for a rounding if you use something like: roundedValue = Math.round(value * 100) * 0.01

Here's a slightly more functional version of the answer m93a provided.

const toFixedNumber = (toFixTo = 2, base = 10) => num => {
  const pow = Math.pow(base, toFixTo)
  return +(Math.round(num * pow) / pow)
}

const oneNumber = 10.12323223

const result1 = toFixedNumber(2)(oneNumber) // 10.12
const result2 = toFixedNumber(3)(oneNumber) // 10.123

// or using pipeline-operator
const result3 = oneNumber |> toFixedNumber(2) // 10.12

For others like me that happen upon this very old question, a modern solution:

const roundValue = (num, decimals = 2) => {
    let scaling = 10 ** decimals;
    return Math.round((num + Number.EPSILON) * scaling) / scaling;
}

ref: https://stackoverflow.com/a/11832950

Be careful using toFixed() and Math.round(), they can produce unexpected results due to the floating point number system:

function toFixedNumber(num, digits, base){
  var pow = Math.pow(base||10, digits);
  return Math.round(num*pow) / pow;
}

console.log(toFixedNumber(130.795, 2, 10));
// 130.79 (incorrect)
console.log(toFixedNumber(100.795, 2, 10));
// 100.8 

console.log(+130.795.toFixed(2));
// 130.79 (incorrect)
console.log(+100.795.toFixed(2));
// 100.8

I recommend using Lodash's _.round() function: https://lodash.com/docs/4.17.15#round

_.round(130.795, 2);
// 130.8