Add String.repeat, String.padLeft, String.padRight.

sdk/lib/_internal/lib/js_string.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of _interceptors;
 
 /**
  * The interceptor class for [String]. The compiler recognizes this
  * class as an interceptor, and changes references to [:this:] to
  * actually use the receiver of the method, which is generated as an extra
@@ skipping 162 matching lines @@
       default:
         return false;
     }
   }
 
   // Dart2js can't use JavaScript trim, because JavaScript does not trim
   // the NEXT LINE character (0x85) and BOMs (0xFEFF).
   String trim() {
     const int CARRIAGE_RETURN = 0x0D;
     const int SPACE = 0x20;
+    const int NEL = 0x85;
+    const int BOM = 0xFEFF;
 
+    // Start by doing JS trim. Then check if it leaves a

[floitsch, 2014/02/19 10:20:36]

Unfinished sentence.

[Søren Gjesse, 2014/02/19 10:44:10]

Leaves a...?

[Lasse Reichstein Nielsen, 2014/02/19 11:43:16]

Done.

+    Strint result = JS("String", "#.trim()", this);

[Søren Gjesse, 2014/02/19 10:44:10]

What type is Strint?

[Lasse Reichstein Nielsen, 2014/02/19 11:43:16]

Done.

+
+    if (result.length == 0) return result;
+    int firstCode = result.codeUnitAt(0);
     int startIndex = 0;
-    while (startIndex < this.length) {
-      int codeUnit = this.codeUnitAt(startIndex);
-      if (codeUnit == SPACE ||
-          codeUnit == CARRIAGE_RETURN ||
-          _isWhitespace(codeUnit)) {
-        startIndex++;
-      } else {
-        break;
+    if (firstCode == NEL || firstCode == BOM) {
+      startIndex++;
+      while (startIndex < result.length) {
+        int codeUnit = result.codeUnitAt(startIndex);
+        if (codeUnit == SPACE ||
+            codeUnit == CARRIAGE_RETURN ||
+            _isWhitespace(codeUnit)) {
+          startIndex++;
+        } else {
+          break;
+        }
+      }
+      if (startIndex == result.length) return "";
+    }
+
+    int endIndex = result.length;
+    // We know that there is at least one character that is non-whitespace.
+    // Therefore we don't need to verify that endIndex > startIndex.
+    int lastCode = result.codeUnitAt(endIndex - 1);
+    if (lastCode == NEL || lastCode == BOM) {
+      endIndex--;
+      while (true) {
+        int codeUnit = result.codeUnitAt(endIndex - 1);
+        if (codeUnit == SPACE ||
+            codeUnit == CARRIAGE_RETURN ||
+            _isWhitespace(codeUnit)) {
+          endIndex--;
+        } else {
+          break;
+        }
       }
     }
-    if (startIndex == this.length) return "";
+    if (startIndex == 0 && endIndex == result.length) return result;
+    return JS('String', r'#.substring(#, #)', result, startIndex, endIndex);
+  }
 
-    int endIndex = this.length;
-    // We know that there is at least one character that is non-whitespace.
-    // Therefore we don't need to verify that endIndex > startIndex.
-    while (true) {
-      int codeUnit = this.codeUnitAt(endIndex - 1);
-      if (codeUnit == SPACE ||
-          codeUnit == CARRIAGE_RETURN ||
-          _isWhitespace(codeUnit)) {
-        endIndex--;
-      } else {
-        break;
-      }
+  String repeat(int times, [String separator = ""]) {
+    if (times < 0) throw new RangeError.value(times);
+    if (times == 0) return "";
+    if (separator.isEmpty) {
+      return JS('String', "new Array(# + 1).join(#)", times, this);
+    } else {
+      var list = new JSArray.growable(times);
+      for (int i = 0; i < times; i++) list[i] = this;
+      return JS('String', "#.join(#)", list, separator);
     }
-    if (startIndex == 0 && endIndex == this.length) return this;
-    return JS('String', r'#.substring(#, #)', this, startIndex, endIndex);
+  }
+
+  String padLeft(int newSize, String padding, { int size }) {
+    if (size == null) {
+      size = this.length;
+    } else if (size < 0) {
+      throw new RangeError.value(size);
+    }
+    int delta = newSize - size;
+    if (delta <= 0) return this;
+    var list = new JSArray.growable(delta + 1);
+    list[delta] = this;
+    return JS("String", "#.join(#)", list, padding);
+  }
+
+  String padRight(int newSize, String padding, { int size }) {
+    if (size == null) {
+      size = this.length;
+    } else if (size < 0) {
+      throw new RangeError.value(size);
+    }
+    int delta = newSize - size;
+    if (delta <= 0) return this;
+    var list = new JSArray.growable(delta + 1);
+    list[0] = this;
+    return JS("String", "#.join(#)", list, padding);
   }
 
   List<int> get codeUnits => new _CodeUnits(this);
 
   Runes get runes => new Runes(this);
 
   int indexOf(Pattern pattern, [int start = 0]) {
     checkNull(pattern);
     if (start is! int) throw new ArgumentError(start);
     if (start < 0 || start > this.length) {
@@ skipping 92 matching lines @@
  */
 class _CodeUnits extends UnmodifiableListBase<int> {
   /** The string that this is the code units of. */
   String _string;
 
   _CodeUnits(this._string);
 
   int get length => _string.length;
   int operator[](int i) => _string.codeUnitAt(i);
 }