Flatten a javascript object to pass as querystring

Question

I have a javascript object that I need to flatten into a string so that I can pass as querystring, how would I do that? i.e:

{ cost: 12345, insertBy: \'testUse

Answer 1

Here's a non-jQuery version:

function toQueryString(obj) {
    var parts = [];
    for (var i in obj) {
        if (obj.hasOwnProperty(i)) {
            parts.push(encodeURIComponent(i) + "=" + encodeURIComponent(obj[i]));
        }
    }
    return parts.join("&");
}

Answer 2

Here is another non-jQuery version that utilizes lodash or underscore if you're already using one of those libraries:

var toQueryString = function(obj) {
  return _.map(obj,function(v,k){
    return encodeURIComponent(k) + '=' + encodeURIComponent(v);
  }).join('&');
};

^ I wrote that 5 years ago. An updated and more succinct version of this would now (Oct 2019) be:

var input = { cost: 12345, insertBy: 'testUser' };
Object.entries(input)
  .map(([k,v]) => `${encodeURIComponent(k)}=${encodeURIComponent(v)}`)
  .join('&');
// cost=12345&insertBy=testUser

Check that the runtime that you're targeting supports Object.entries() or that you're using a transpiler like Babel or TypeScript if it doesn't.

Answer 3

Another version:

function toQueryString(obj) {
    return Object.keys(obj).map(k => {
      return encodeURIComponent(k) + "=" + encodeURIComponent(obj[k])
    })
    .join("&");
}

Answer 4

you can use this

function serialize(obj)
{
    let str = []

    for(var p in obj)
    {
      if(obj.hasOwnProperty(p)) str.push(encodeURIComponent(p) + '=' + encodeURIComponent(obj[p]))
    }

    return str.join('&')
}

try on JSFiddle on this link https://jsfiddle.net/yussan/kwmnkca6/

Answer 5

You want jQuery.param:

var str = $.param({ cost: 12345, insertBy: 'testUser' });
// "cost=12345&insertBy=testUser"

Note that this is the function used internally by jQuery to serialize objects passed as the data argument.

Answer 6

Using Lodash library it can be done as:

let data = {}

_.map(data, (value, key) => `${key}=${value}`)
.join("&");

Note that this library has been imported as:

window._ = require('lodash');