round a number to the nearest thousandth in javascript

In javascript, you can round a number to the nearest thousandth by using the toFixed() method on a number and passing in the precision you want. The precision specifies the number of digits to the right of the decimal point.

Here's an example:

index.tsx
let num = 123.456789;
let roundedNum = num.toFixed(3); 

console.log(roundedNum); // Output: 123.457
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In the example above, the toFixed() method takes in the number 3, which specifies that we want to round the number num to the nearest thousandth. The resulting roundedNum will have a precision of 3 decimal places.

Note that the toFixed() method returns a string, so if you need to perform further mathematical operations on the rounded number, you may need to convert it back to a number using parseFloat() or Number().