Alternatives to delete?

Question

I've been looking through a lot of blog posts, documentation, etc. about JavaScript's strict mode.

I noticed that there are a lot of restrictions on the delete keyword. I don't even know if you could call them restrictions. It seems like delete just no longer works.

I would love to use strict mode. It's a great idea. But I also think delete is a great idea.

Are there any alternative ways to "delete" a variable?

Answer 1

You do not delete variables.

delete is used to remove a property from an object.

delete foo.a will remove property "a" from object foo.

Why do you need to remove a local variable from scope? You can just set the variable to be undefined

(function(undefined) {
    // undefined is undefined.
})();

(function() {
    var undefined; // undefined is undefined
})();

Another way to check againts undefined would be doing foo === void 0 since void is an operator which runs the expression following it and returns undefined. It's a clever trick.

Answer 2

How about just setting your variables to null? Once you set the variables to null, the JavaScript garbage collector will delete any unreferenced variables on next run.

HTH.

EDIT: As @chris Buckler mentioned in the comments, this can't be done at global scope, as global variables never get garbage collected.