2013 NEWS 2013-05-26 - New Uize.isArguments Method
The new Uize.isArguments method, implemented in the Uize base module, tests if a value is a function arguments object.
SYNTAX
isArgumentsBOOL = Uize.isArguments (valueANYTYPE);
A value is considered an arguments object if, and only if, the value is a reference to an instance of JavaScript's built-in Arguments object. Arguments objects are created when calling functions in JavaScript and are referenced within a called function by the special arguments keyword.
While an arguments object is listy in nature (i.e. it is an object having a length property whose value is a number), listy objects that are not instances of JavaScript's Arguments object are not considered arguments objects by the Uize.isArguments method. So, for example, the array ['foo','bar'] is not considered an arguments object, nor is the listy object {0:'foo',1:'bar',length:2}.
The Uize.isArguments method is useful when wanting to distinguish between an arguments object and other listy objects in order to conditionalize the behavior for a function.
EXAMPLES
Uize.isArguments ((function () {return arguments}) ('foo','bar')); // return true
Uize.isArguments ((function () {return arguments}) ()); // return true
Uize.isArguments (['foo','bar']); // return false
Uize.isArguments ({0:'foo',1:'bar',length:2}); // return false
Uize.isArguments ({foo:'bar'}); // return false
Uize.isArguments (function () {}); // return false
Uize.isArguments (/foo/gi); // return false
Uize.isArguments ('foo'); // return false
Uize.isArguments (true); // return false
Uize.isArguments (42); // return false
Uize.isArguments (undefined); // return false
Uize.isArguments (null); // return false
1. Unit Tested and Documented
The new Uize.isArguments method is comprehensively unit tested and documented.
2. Improved Uize.forEach Method
The impetus for providing the Uize.isArguments method came out of the desire to have the Uize.forEach method support iterating over the arguments of a function's arguments object, while still preserving the behavior of iterating over all the properties of other objects (including listy objects).
The Uize.isArguments method lets the Uize.forEach method distinguish between function arguments objects and other objects. Since the code was going to be added to the Uize module for the benefit of the Uize.forEach method, it was decided to expose it through a dedicated static method for the benefit of anybody else who might like to use it. So, with this update, the Uize.forEach method now supports iterating over the arguments in an arguments list.