How to get the smallest fractional number correct to x decimal places?-CodePudding

Given some number of decimal places, how can I get the smallest number that matches those decimals?

E.g.

For 3 decimal places, it would be 0.001.

For 5 decimal places, it would be 0.00001.

For 0 decimal places, it would be 0

...and so on

CodePudding user response：

Math.pow can help:

console.log(10 ** -1); // 0.1
console.log(10 ** -2); // 0.01
console.log(10 ** -3); // 0.001

So if n is the amount of decimals you want, do Math.pow(10, -n)

copy-paste-ready function:

function smallestFractionalNumberWithDecimals(n) {
  if (n <= 0) {
    return 0;
  }
  return Math.pow(10, -n);
}

only exception is for n=0 because Math.pow(10, 0) is 1

CodePudding user response：

The below logic can be one way to do what you want to generate:

function generate(n) {
    if (n >= 0) {
        return (n === 0) ? 0 : 1 / Math.pow(10, n);
    }
    else {
        return -1;
    }
}

console.log(generate(3));
console.log(generate(5));
console.log(generate(0));