Question

I recently saw code that looks like this:

(function (someGlobal) {
    someGlobal.DoSomething();
})(someGlobal);

where someGlobal was a large framework class. It could be JQuery. What is the benefit of doing this? Is it a good practice? It seems like this code would be equivalent and less error prone because you don’t hide the global:

(function () {
    someGlobal.DoSomething();
})();

Answer 1

• You have a reliable reference in case the global one gets overwritten

• It shortens the scope chain to access it

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“It seems like this code would be equivalent and less error prone because you don’t hide the global:“

(function () {
    someGlobal.DoSomething();
})();

If you anticipate the global being overwritten, and your code relies on the overwritten value, then clearly you wouldn’t want to shadow it by a local variable in a function.

Aside from that, the local reference in a function shouldn’t be any more prone to error.