JavaScript: String.prototype.padStart
New in JS2017.
str.padStart(n)
-
Add spaces in front so the length is n. Return the new string.
console.log("x".padStart(3) === " x");
str.padStart(n, padstr)
-
Use padStr to pad.
console.log( "x".padStart(3, "0") === "00x", "x".padStart(4, "ab") === "abax", );
/* no padding happens, because "ð" is already length 2 */ console.log("ð".padStart(2, "x") === "ð"); /* ð name: FACE WITH TEARS OF JOY codepoint decimal: 128514 codepoint hexadecimal: 1f602 UTF8 encoding: F0 9F 98 82 Utf16 encoding: D8 3D DE 02 */
Note: "ð".length === 2
[see JavaScript: String Code Unit]