sdk/lib/html/src/_Collections.dart

// Copyright (c) 2011, 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.

/**
 * The [Collections] class implements static methods useful when
 * writing a class that implements [Collection] and the [iterator]
 * method.
 */
class _Collections {
  static bool contains(Iterable<Object> iterable, Object element) {
    for (final e in iterable) {
      if (e == element) return true;
    }
    return false;
  }

  static void forEach(Iterable<Object> iterable, void f(Object o)) {
    for (final e in iterable) {
      f(e);
    }
  }

  static List map(Iterable<Object> source,
                  List<Object> destination,
                  f(o)) {
    for (final e in source) {
      destination.add(f(e));
    }
    return destination;
  }

  static bool some(Iterable<Object> iterable, bool f(Object o)) {
    for (final e in iterable) {
      if (f(e)) return true;
    }
    return false;
  }

  static bool every(Iterable<Object> iterable, bool f(Object o)) {
    for (final e in iterable) {
      if (!f(e)) return false;
    }
    return true;
  }

  static List filter(Iterable<Object> source,
                     List<Object> destination,
                     bool f(o)) {
    for (final e in source) {
      if (f(e)) destination.add(e);
    }
    return destination;
  }

  static bool isEmpty(Iterable<Object> iterable) {
    return !iterable.iterator().hasNext;
  }
}