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How would you overload the [] operator in javascript
Is it possible to overload the [] operator for arrays in Javascript?
For instance I would like to modify the behavior of the bracket so that when it accesses an index out of range it returns 0 instead of undedined.
I know I could probably get away with something like this:
function get(array, i) {
return array[i] || 0;
}
But that's not really modifying the behavior of arrays the way I want.
Since [] is not an operator, you can't "override" it, but you can add property to Array's prototype, which may be helpful in your specific case. Hovewer, it is a bad practice:
Array.prototype.get = function(i, fallback) { return this[i] || fallback; }
a = [1, 2, 3]
a.get(0, 42)
1
a.get(4, 42)
42
[] is not an operator, and you can't override it.
You can override accessors for other javascript objects (that is override ['somespecificvalue'] for writing or reading) but not the [] of arrays.
I'll add I'm glad you can't override it. I don't see the point except in making a whole application unreadable (an application where the basic syntactic elements can't be understood before you've read the whole code to be sure there isn't a change is unreadable).
[]characters.