CODEWITHSUNDEEP
javascriptnode.jssortingquery-string
krl
krl

Reputation: 5296

Sorted parameters in query string from two JavaScript object in Node.js

What's the best way to receive a sorted parameter query string from two JavaScript objects using querystring, qs, etc?

I am adding properties from obj2 to obj1:

for (var attrname in obj2) { obj1[attrname] = obj2[attrname]; }

obj1 ends up with a bunch of properties.

After I stringify obj1, I need all parameters in the query string to be alphabetically sorted by key:

a=v1&b=v2&c=v3

Upvotes: 0

Views: 4313

Answers (1)

Guffa
Guffa

Reputation: 700650

As object properties can not be sorted (their order is unspecified), you would need to put them in an array.

You can make an object that handles a key-value pair:

function KeyValue(key, value) {
  this.key = key;
  this.value = value;
}

KeyValue.prototype = {
  toString: function() {
    return encodeURIComponent(this.key) + '=' + encodeURIComponent(this.value);
  }
};

By creating an array of KeyValue objects from the properties in the object, you can then sort them on the key, and just use join to make the query string:

var obj1 = { x: '1 2 3', b: 42, f: 'x<y' };

var query = [];
for (var key in obj1) {
    if (obj1.hasOwnProperty(key)) {
        query.push(new KeyValue(key, obj1[key]));
    }
}

query.sort(function(a, b){ return a.key < b.key ? -1 : 1 });

var queryString = query.join('&');

The variable queryString now contains b=42&f=x%3Cy&x=1%202%203.

Demo: http://jsfiddle.net/915wt4j4/

Upvotes: 4

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