Simplifying padLeft() to only allow spaces or zeros for padding. Updated padRight() to mirror padLeft() but without the option to use zeros since that would be an unlikely use case.

Author: rhillefeld

src/compiler/core.ts

@@ -2252,38 +2252,24 @@ namespace ts {
 
 
     /**
-     * Returns 's' left-padded with copies of 'padString' until it reaches the given 'length'.
-     * If omitted, 'padString' defaults to a single space.
-     * If 'length' is less than or equal to 's.length' or 'padString' is empty, returns 's' unchanged.
+     * Returns string left-padded with spaces or zeros until it reaches the given length.
+     *
+     * @param s String to pad.
+     * @param length Final padded length. If less than or equal to 's.length', returns 's' unchanged.
+     * @param padString Character to use as padding (default " ").
      */
-    export function padLeft(s: string, length: number, padString = " ") {
-        if (length <= s.length || padString.length === 0) {
-            return s;
-        }
-        else {
-            length -= s.length;                 // how much padding we need
-            if (length > padString.length) {    // need more than one copy of padString
-                padString += padString.repeat(length / padString.length);
-            }
-            return padString.slice(0, length) + s;
-        }
+    export function padLeft(s: string, length: number, padString: " " | "0" = " ") {
+        return length <= s.length ? s : padString.repeat(length - s.length) + s;
     }
 
     /**
-     * Returns 's' right-padded with copies of 'padString' until it reaches the given 'length'.
-     * If omitted, 'padString' defaults to a single space.
-     * If 'length' is less than or equal to 's.length' or 'padString' is empty, returns 's' unchanged.
+     * Returns string right-padded with spaces until it reaches the given length.
+     *
+     * @param s String to pad.
+     * @param length Final padded length. If less than or equal to 's.length', returns 's' unchanged.
+     * @param padString Character to use as padding (default " ").
      */
-    export function padRight(s: string, length: number, padString = " ") {
-        if (length <= s.length || padString.length === 0) {
-            return s;
-        }
-        else {
-            length -= s.length;
-            if (length > padString.length) {    // need more than one copy of padString
-                padString += padString.repeat(length / padString.length);
-            }
-            return s + padString.slice(0, length);
-        }
+    export function padRight(s: string, length: number, padString: " " = " ") {
+        return length <= s.length ? s : s + padString.repeat(length - s.length);
     }
 }