Useful JavaScript Game Extensions: Array#each

Welcome to the nether realm of JavaScript extensions… things that should exist and sometimes kind of do, but with a different name and an inconsiderate API.

Part 6 of 256 Useful JavaScript Extensions Array#each.

/**
 * Call the given iterator once for each element in the array,
 * passing in the element as the first argument, the index of
 * the element as the second argument, and this array as the
 * third argument.
 *
 * @param {Function} iterator Function to be called once for
 * each element in the array.
 * @param {Object} [context] Optional context parameter to be
 * used as `this` when calling the iterator function.
 *
 * @returns `this` to enable method chaining.
 */
Array.prototype.each = function(iterator, context) {
  if(this.forEach) {
    this.forEach(iterator, context);
  } else {
    var len = this.length;
    for(var i = 0; i < len; i++) {
      iterator.call(context, this[i], i, this);
    }
  }

  return this;
};

You’ll notice that this method makes use of the possibly existing Array#forEach method if it exists. In fact it is almost an alias of it, but since forEach always returns undefined like a jerk, we need to wrap it and return the object for chaining like a good citizen. Also, who wants to always be writing forEach, why not just each? Yeah… I like this.

// Example:

var people = [{name: "David"}, {name: "Joe"}, {name: "Gandalf"}];

// Greet each person by name
people.each(function(person) {
  alert("Hi " + person.name + "!");
});

Author: Daniel X

Heretic priest of the Machine God. I enjoy crawling around in Jeff Bezo's spaceship, bringing technology to the people, and long walks outside of time and space. View all posts by Daniel X