For loops

You can iterate with the standard for loop. For example:

  1. var message = StringBuffer('Dart is fun');
  2. for (var i = 0; i < 5; i++) {
  3.   message.write('!');
  4. }

Closures inside of Dart’s for loops capture the value of the index,avoiding a common pitfall found in JavaScript. For example, consider:

  1. var callbacks = [];
  2. for (var i = 0; i < 2; i++) {
  3.   callbacks.add(() => print(i));
  4. }
  5. callbacks.forEach((c) => c());

The output is 0 and then 1, as expected. In contrast, the examplewould print 2 and then 2 in JavaScript.

If the object that you are iterating over is an Iterable, you can use theforEach() method. Using forEach() is a good option if you don’t need toknow the current iteration counter:

  1. candidates.forEach((candidate) => candidate.interview());

Iterable classes such as List and Set also support the for-in form ofiteration:

  1. var collection = [0, 1, 2];
  2. for (var x in collection) {
  3.   print(x); // 0 1 2
  4. }