CODEWITHSUNDEEP
javascriptjquery
Rajat Gupta
Rajat Gupta

Reputation: 26605

Javascript object that maps keys to value & allows iteration over keys

I need to create object in javascript that allows to fetch values using keys & also iterate over keys. The primary requirement is fetching value by key but iteration is required to maintain sort order of entries by values(integer).

How do I go about creating such an object ?

Upvotes: 0

Views: 3132

Answers (3)

Wayne
Wayne

Reputation: 60424

Native objects don't support exactly what you're looking for, but it's fairly straightforward to create a wrapper around native objects that provides extra functionality.

A possible approach:

function KeySortArr(obj) {
    this.obj = obj || {};
}

KeySortArr.prototype = {
    get: function(key) {
        return this.obj[key];
    },

    set: function(key, value) {
        this.obj[key] = value;
    },

    keys: function() {
        var keys = [];
        for(var i in this.obj) {
            if (this.obj.hasOwnProperty(i))
                keys.push(i);
        }
        return keys;
    },

    getKeysSortedByValue: function() {
        var obj = this.obj;
        return this.keys().sort(function(a, b) {
            return obj[a] > obj[b];
        });
    }
};

Usage:

var arr = new KeySortArr();
arr.set("test", 4);
arr.set("another", 2);
arr.set("ok", 60);
arr.set("last", 14);

The following then:

arr.getKeysSortedByValue();

Returns:

["another, "test", "last", "ok"]

In other words, the keys are sorted by their associated value. This might not be exactly what you were looking for, but it should be close.

Upvotes: 0

Apurv
Apurv

Reputation: 309

sampleJson={
"1":"john",
"2":"johny"
}

You can iterate using for in loop

for(key in sampleJson){
//ur code
}

Upvotes: 1

ColinE
ColinE

Reputation: 70162

  1. All objects in JavaScript are JSONeable! (is that really a word).
  2. All objects in JavaScript are a collection of key value mappings.
  3. A for in loop iterates over the keys of an object.

Upvotes: 1

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