Update _string

Author: viniciuspugliese

modules/_string

@@ -19,3 +19,20 @@ if (!String.prototype.startsWith) {
         return this.indexOf(searchString, position) === position;
     };
 }
+
+if (!String.prototype.padStart) {
+    String.prototype.padStart = function padStart(targetLength,padString) {
+        targetLength = targetLength>>0; //truncate if number or convert non-number to 0;
+        padString = String((typeof padString !== 'undefined' ? padString : ' '));
+        if (this.length > targetLength) {
+            return String(this);
+        }
+        else {
+            targetLength = targetLength-this.length;
+            if (targetLength > padString.length) {
+                padString += padString.repeat(targetLength/padString.length); //append to original to ensure we are longer than needed
+            }
+            return padString.slice(0,targetLength) + String(this);
+        }
+    };
+}