Javascript HashTable use Object key

Here is a simple Map implementation that will work with any type of key, including object references, and it will not mutate the key in any way:

function Map() {
    var keys = [], values = [];

    return {
        put: function (key, value) {
            var index = keys.indexOf(key);
            if(index == -1) {
            else {
                values[index] = value;
        get: function (key) {
            return values[keys.indexOf(key)];

While this yields the same functionality as a hash table, it’s not actually implemented using a hash function since it iterates over arrays and has a worst case performance of O(n). However, for the vast majority of sensible use cases this shouldn’t be a problem at all. The indexOf function is implemented by the JavaScript engine and is highly optimized.

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