JS: Number.prototype.toPrecision

By Xah Lee. Date: . Last updated: .
number.toPrecision(n)
  • Return a string representation of number, with n significant digits.
  • Result may be in exponential notation. e.g. "1e+1" meaning 1*10^1, or 10.
  • If n is undefined, call ToString instead.
console.log((3.123).toPrecision(1) === "3");
console.log((3.123).toPrecision(2) === "3.1");
console.log((3.123).toPrecision(3) === "3.12");
console.log((3.123).toPrecision(4) === "3.123");
console.log((3.123).toPrecision(5) === "3.1230");
console.log((12.345).toPrecision(1) === "1e+1");
console.log((12.345).toPrecision(2) === "12");
console.log((12.345).toPrecision(3) === "12.3");
console.log((0.123).toPrecision(1) === "0.1");
console.log((0.123).toPrecision(2) === "0.12");
console.log((0.123).toPrecision(3) === "0.123");