Aggregate CSS manipulation functions in html lib.

tools/dom/src/CssClassSet.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 html;
-
-abstract class CssClassSet implements Set<String> {
-
-  String toString() {
-    return readClasses().join(' ');
-  }
-
-  /**
-   * Adds the class [value] to the element if it is not on it, removes it if it
-   * is.
-   */
-  bool toggle(String value) {
-    Set<String> s = readClasses();
-    bool result = false;
-    if (s.contains(value)) {
-      s.remove(value);
-    } else {
-      s.add(value);
-      result = true;
-    }
-    writeClasses(s);
-    return result;
-  }
-
-  /**
-   * Returns [:true:] if classes cannot be added or removed from this
-   * [:CssClassSet:].
-   */
-  bool get frozen => false;
-
-  // interface Iterable - BEGIN
-  Iterator<String> get iterator => readClasses().iterator;
-  // interface Iterable - END
-
-  // interface Collection - BEGIN
-  void forEach(void f(String element)) {
-    readClasses().forEach(f);
-  }
-
-  String join([String separator = ""]) => readClasses().join(separator);
-
-  Iterable map(f(String element)) => readClasses().map(f);
-
-  Iterable<String> where(bool f(String element)) => readClasses().where(f);
-
-  Iterable expand(Iterable f(String element)) => readClasses().expand(f);
-
-  bool every(bool f(String element)) => readClasses().every(f);
-
-  bool any(bool f(String element)) => readClasses().any(f);
-
-  bool get isEmpty => readClasses().isEmpty;
-
-  int get length => readClasses().length;
-
-  String reduce(String combine(String value, String element)) {
-    return readClasses().reduce(combine);
-  }
-
-  dynamic fold(dynamic initialValue,
-      dynamic combine(dynamic previousValue, String element)) {
-    return readClasses().fold(initialValue, combine);
-  }
-  // interface Collection - END
-
-  // interface Set - BEGIN
-  /**
-   * Determine if this element contains the class [value].
-   *
-   * This is the Dart equivalent of jQuery's
-   * [hasClass](http://api.jquery.com/hasClass/).
-   */
-  bool contains(String value) => readClasses().contains(value);
-
-  /**
-   * Add the class [value] to element.
-   *
-   * This is the Dart equivalent of jQuery's
-   * [addClass](http://api.jquery.com/addClass/).
-   */
-  void add(String value) {
-    // TODO - figure out if we need to do any validation here
-    // or if the browser natively does enough.
-    _modify((s) => s.add(value));
-  }
-
-  /**
-   * Remove the class [value] from element, and return true on successful
-   * removal.
-   *
-   * This is the Dart equivalent of jQuery's
-   * [removeClass](http://api.jquery.com/removeClass/).
-   */
-  bool remove(Object value) {
-    if (value is! String) return false;
-    Set<String> s = readClasses();
-    bool result = s.remove(value);
-    writeClasses(s);
-    return result;
-  }
-
-  /**
-   * Add all classes specified in [iterable] to element.
-   *
-   * This is the Dart equivalent of jQuery's
-   * [addClass](http://api.jquery.com/addClass/).
-   */
-  void addAll(Iterable<String> iterable) {
-    // TODO - see comment above about validation.
-    _modify((s) => s.addAll(iterable));
-  }
-
-  /**
-   * Remove all classes specified in [iterable] from element.
-   *
-   * This is the Dart equivalent of jQuery's
-   * [removeClass](http://api.jquery.com/removeClass/).
-   */
-  void removeAll(Iterable<String> iterable) {
-    _modify((s) => s.removeAll(iterable));
-  }
-
-  /**
-   * Toggles all classes specified in [iterable] on element.
-   *
-   * Iterate through [iterable]'s items, and add it if it is not on it, or
-   * remove it if it is. This is the Dart equivalent of jQuery's
-   * [toggleClass](http://api.jquery.com/toggleClass/).
-   */
-  void toggleAll(Iterable<String> iterable) {
-    iterable.forEach(toggle);
-  }
-
-  void retainAll(Iterable<String> iterable) {
-    _modify((s) => s.retainAll(iterable));
-  }
-
-  void removeWhere(bool test(String name)) {
-    _modify((s) => s.removeWhere(test));
-  }
-
-  void retainWhere(bool test(String name)) {
-    _modify((s) => s.retainWhere(test));
-  }
-
-  bool containsAll(Iterable<String> collection) =>
-    readClasses().containsAll(collection);
-
-  Set<String> intersection(Set<String> other) =>
-    readClasses().intersection(other);
-
-  Set<String> union(Set<String> other) =>
-    readClasses().union(other);
-
-  Set<String> difference(Set<String> other) =>
-    readClasses().difference(other);
-
-  String get first => readClasses().first;
-  String get last => readClasses().last;
-  String get single => readClasses().single;
-  List<String> toList({ bool growable: true }) =>
-      readClasses().toList(growable: growable);
-  Set<String> toSet() => readClasses().toSet();
-  Iterable<String> take(int n) => readClasses().take(n);
-  Iterable<String> takeWhile(bool test(String value)) =>
-      readClasses().takeWhile(test);
-  Iterable<String> skip(int n) => readClasses().skip(n);
-  Iterable<String> skipWhile(bool test(String value)) =>
-      readClasses().skipWhile(test);
-  String firstWhere(bool test(String value), { String orElse() }) =>
-      readClasses().firstWhere(test, orElse: orElse);
-  String lastWhere(bool test(String value), {String orElse()}) =>
-      readClasses().lastWhere(test, orElse: orElse);
-  String singleWhere(bool test(String value)) =>
-      readClasses().singleWhere(test);
-  String elementAt(int index) => readClasses().elementAt(index);
-
-  void clear() {
-    _modify((s) => s.clear());
-  }
-  // interface Set - END
-
-  /**
-   * Helper method used to modify the set of css classes on this element.
-   *
-   *   f - callback with:
-   *   s - a Set of all the css class name currently on this element.
-   *
-   *   After f returns, the modified set is written to the
-   *       className property of this element.
-   */
-  void _modify( f(Set<String> s)) {
-    Set<String> s = readClasses();
-    f(s);
-    writeClasses(s);
-  }
-
-  /**
-   * Read the class names from the Element class property,
-   * and put them into a set (duplicates are discarded).
-   * This is intended to be overridden by specific implementations.
-   */
-  Set<String> readClasses();
-
-  /**
-   * Join all the elements of a set into one string and write
-   * back to the element.
-   * This is intended to be overridden by specific implementations.
-   */
-  void writeClasses(Set<String> s);
-}