Differentiating between arrays and “hashes” in Javascript

Question

In order to make the syntax for one of my functions nicer, I need to be able to tell whether a specific parameter is an array or \"hash\" (which I know are just objects).

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Answer 1

This typeof function is used to correct the array/object clash for the typeof operator, and the null/object clash. It does not however work across frames or across windows. See the source for a more advanced version that works across these.

function typeOf(value) {
    var s = typeof value;
    if (s === 'object') {
        if (value) {
            if (value instanceof Array) {
                s = 'array';
            }
        } else {
            s = 'null';
        }
    }
    return s;
}

Source: Douglas Crockford's Javascript site