[patch] [cla] Dojo array iteration methods deviate from spec on sparse arrays

[Ben Lowery]

dojo.forEach doesn't follow the spec at ​https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Objects/Array/forEach and incorrectly fires the callback provided for undefined keys in a sparse array. For example:

var arr = [];
arr[1] = "foo"'
arr[5] = "bar";

// this prints 6 times
dojo.forEach(arr, function(n,i) { console.log("%d: %s", i, n); });

// this prints twice
arr.forEach(function(n, i) { console.log("%d: %s", i, n); });

dojo's forEach should be checking to ensure that each key from the for loop is present in the array before firing the callback. See the example implementation provided at ​https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Objects/Array/forEach#Compatibility for further illustration.

[Ben Lowery]

Patch that fixes sparse array iteration

[Ben Lowery]

Here's a patch that fixes the iteration methods, along with supporting tests.

[James Burke]

As discussed on list, we will defer this to 2.0 when we can also consider delegating back to native methods.

[bill]

The discussion is in ​http://thread.gmane.org/gmane.comp.web.dojo.devel/11475.

Let's be careful whether or not we do in 2.0. Although the current behavior is different than Array.forEach(), it shouldn't be considered a bug. Enhancing forEach() to walk sparse arrays will slow down all versions of IE, and unclear of the effect on other browsers (see [10200]).

[James Burke]

(In [20229]) Refs #9942, adds a note to dojo.forEach about operating over sparse arrays, and updates devmo links for the different array methods.

[Eugene Lazutkin]

All array method docs should be updated --- the standard allows sparse arrays on all of them, we support none.

[Ben Lowery]

(In [20232]) refs #9942. Adds in doc updates for the other array iteration methods indicating our difference with sparse arrays.

[Ben Lowery]

(In [20233]) refs #9942. Minor doc consistency fixes for the sparse array warning.

[Ben Lowery]

Updated the remaining docs.

[Ben Lowery]

Updating the title a bit to reflect what's really the matter.

[Kitson Kelly]

Dojo 2.0 will only support ES5 user agents, the array routines (which pre-dated ES5) will not be present in Dojo 2.0, so closing the ticket.