I am using a JavaScript object as a dictionary, and wanted to make keys case-insensitive. I used Object.defineProperty() to implement this:

Object.defineProperty(Object.prototype, "getKeyUpperCase", {
    value: function(prop) {
        for (var key in this) {
            if (key.toUpperCase() === prop.toUpperCase()) {
                return this[key];
            };
        };
    },
    enumerable: false
});

What is the time complexity of searching an object via key in JavaScript? I'm expecting the dictionary to hold around 1 million keys.

To me it looks like worst case would be O(n), best case would be O(1) and average case would be O(n/2). Is this correct?

Would it be substantially more efficient to retrieve the object's keys as an array (Object.Keys(dictionary).map(function(key) return key.toUpperCase()).sort()) to check if the key exists? Am I correct in saying that the average time complexity of this operation is O(log n)

Usage of the dictionary is along the lines of this:

var dictionary = {/* some million keys or so* /};
var oldKey = someSmallArray[i];
var newValue = dictionary.getKeyUpperCase(oldKey.trim().toUpperCase());

I am using a JavaScript object as a dictionary, and wanted to make keys case-insensitive. I used Object.defineProperty() to implement this:

Object.defineProperty(Object.prototype, "getKeyUpperCase", {
    value: function(prop) {
        for (var key in this) {
            if (key.toUpperCase() === prop.toUpperCase()) {
                return this[key];
            };
        };
    },
    enumerable: false
});

What is the time complexity of searching an object via key in JavaScript? I'm expecting the dictionary to hold around 1 million keys.

To me it looks like worst case would be O(n), best case would be O(1) and average case would be O(n/2). Is this correct?

Would it be substantially more efficient to retrieve the object's keys as an array (Object.Keys(dictionary).map(function(key) return key.toUpperCase()).sort()) to check if the key exists? Am I correct in saying that the average time complexity of this operation is O(log n)?

Usage of the dictionary is along the lines of this:

var dictionary = {/* some million keys or so */};
var oldKey = someSmallArray[i];
var newValue = dictionary.getKeyUpperCase(oldKey.trim().toUpperCase());