JavaScript: String.leftPad()

String.leftPad.js

/**
 * Pad a string to a certain length with another string.
 *
 * @param {Number} size The resulting padded string length.
 * @param {String} [str=" "] String to use as padding.
 * @returns {String} The padded string.
 */
if (!String.prototype.leftPad) {
	String.prototype.leftPad = function (length, str) {
		if (this.length >= length) {
			return this;
		}
		str = str || ' ';
		return (new Array(Math.ceil((length - this.length) / str.length) + 1).join(str)).substr(0, (length - this.length)) + this;
	};
}

The call to substr() is vestigial since you are already defining the length of the pad with the size of the array object. Also, since you're creating an array, you could simply push the original str to the end of it before the join(), making sure to remove the ' + 1' from the initial size.

a = new Array((((length - this.length) / str.length) | 0));
a.push(this);
return a.join(str);

ATERNOS USE THIS:0

FR