How to serialize an Object into a list of URL query parameters?
JavascriptJavascript Problem Overview
Without knowing the keys of a JavaScript Object, how can I turn something like...
var obj = {
param1: 'something',
param2: 'somethingelse',
param3: 'another'
}
obj[param4] = 'yetanother';
...into...
var str = 'param1=something¶m2=somethingelse¶m3=another¶m4=yetanother';
...?
Javascript Solutions
Solution 1 - Javascript
One line with no dependencies:
new URLSearchParams(obj).toString();
// OUT: param1=something¶m2=somethingelse¶m3=another¶m4=yetanother
Use it with the URL builtin like so:
let obj = { param1: 'something', param2: 'somethingelse', param3: 'another' }
obj['param4'] = 'yetanother';
const url = new URL(`your_url.com`);
url.search = new URLSearchParams(obj);
const response = await fetch(url);
[Edit April 4, 2020]: null values will be interpreted as the string 'null'.
[Edit Mar 9, 2022]: browser compatibility
Solution 2 - Javascript
If you use jQuery, this is what it uses for parameterizing the options of a GET XHR request:
$.param( obj )
Solution 3 - Javascript
An elegant one: (assuming you are running a modern browser or node)
var str = Object.keys(obj).map(function(key) {
return key + '=' + obj[key];
}).join('&');
And the ES2017 equivalent: (thanks to Lukas)
let str = Object.entries(obj).map(([key, val]) => `${key}=${val}`).join('&');
Note: You probably want to use encodeURIComponent() if the keys/values are not URL encoded.
Solution 4 - Javascript
var str = "";
for (var key in obj) {
if (str != "") {
str += "&";
}
str += key + "=" + encodeURIComponent(obj[key]);
}
Example: http://jsfiddle.net/WFPen/
Solution 5 - Javascript
> ES2017 approach
Object.entries(obj).map(([key, val]) => `${key}=${encodeURIComponent(val)}`).join('&')
Solution 6 - Javascript
ES6:
function params(data) {
return Object.keys(data).map(key => `${key}=${encodeURIComponent(data[key])}`).join('&');
}
console.log(params({foo: 'bar'}));
console.log(params({foo: 'bar', baz: 'qux$'}));
Solution 7 - Javascript
For one level deep...
var serialiseObject = function(obj) {
var pairs = [];
for (var prop in obj) {
if (!obj.hasOwnProperty(prop)) {
continue;
}
pairs.push(prop + '=' + obj[prop]);
}
return pairs.join('&');
}
There was talk about a recursive function for arbitrarily deep objects...
var serialiseObject = function(obj) {
var pairs = [];
for (var prop in obj) {
if (!obj.hasOwnProperty(prop)) {
continue;
}
if (Object.prototype.toString.call(obj[prop]) == '[object Object]') {
pairs.push(serialiseObject(obj[prop]));
continue;
}
pairs.push(prop + '=' + obj[prop]);
}
return pairs.join('&');
}
This of course means that the nesting context is lost in the serialisation.
If the values are not URL encoded to begin with, and you intend to use them in a URL, check out JavaScript's encodeURIComponent().
Solution 8 - Javascript
If you're using NodeJS 13.1 or superior you can use the native querystring module to parse query strings.
const qs = require('querystring');
let str = qs.stringify(obj)
Solution 9 - Javascript
Object.keys(obj).map(k => `${encodeURIComponent(k)}=${encodeURIComponent(obj[k])}`).join('&')
Solution 10 - Javascript
Since I made such a big deal about a recursive function, here is my own version.
function objectParametize(obj, delimeter, q) {
var str = new Array();
if (!delimeter) delimeter = '&';
for (var key in obj) {
switch (typeof obj[key]) {
case 'string':
case 'number':
str[str.length] = key + '=' + obj[key];
break;
case 'object':
str[str.length] = objectParametize(obj[key], delimeter);
}
}
return (q === true ? '?' : '') + str.join(delimeter);
}
Solution 11 - Javascript
Just for the record and in case you have a browser supporting ES6, here's a solution with reduce:
Object.keys(obj).reduce((prev, key, i) => (
`${prev}${i!==0?'&':''}${key}=${obj[key]}`
), '');
And here's a snippet in action!
// Just for test purposes
let obj = {param1: 12, param2: "test"};
// Actual solution
let result = Object.keys(obj).reduce((prev, key, i) => (
`${prev}${i!==0?'&':''}${key}=${obj[key]}`
), '');
// Run the snippet to show what happens!
console.log(result);
Solution 12 - Javascript
A useful code when you have the array in your query:
var queryString = Object.keys(query).map(key => {
if (query[key].constructor === Array) {
var theArrSerialized = ''
for (let singleArrIndex of query[key]) {
theArrSerialized = theArrSerialized + key + '[]=' + singleArrIndex + '&'
}
return theArrSerialized
}
else {
return key + '=' + query[key] + '&'
}
}
).join('');
console.log('?' + queryString)
Solution 13 - Javascript
If you need a recursive function that will produce proper URL parameters based on the object given, try my Coffee-Script one.
@toParams = (params) ->
pairs = []
do proc = (object=params, prefix=null) ->
for own key, value of object
if value instanceof Array
for el, i in value
proc(el, if prefix? then "#{prefix}[#{key}][]" else "#{key}[]")
else if value instanceof Object
if prefix?
prefix += "[#{key}]"
else
prefix = key
proc(value, prefix)
else
pairs.push(if prefix? then "#{prefix}[#{key}]=#{value}" else "#{key}=#{value}")
pairs.join('&')
or the JavaScript compiled...
toParams = function(params) {
var pairs, proc;
pairs = [];
(proc = function(object, prefix) {
var el, i, key, value, _results;
if (object == null) object = params;
if (prefix == null) prefix = null;
_results = [];
for (key in object) {
if (!__hasProp.call(object, key)) continue;
value = object[key];
if (value instanceof Array) {
_results.push((function() {
var _len, _results2;
_results2 = [];
for (i = 0, _len = value.length; i < _len; i++) {
el = value[i];
_results2.push(proc(el, prefix != null ? "" + prefix + "[" + key + "][]" : "" + key + "[]"));
}
return _results2;
})());
} else if (value instanceof Object) {
if (prefix != null) {
prefix += "[" + key + "]";
} else {
prefix = key;
}
_results.push(proc(value, prefix));
} else {
_results.push(pairs.push(prefix != null ? "" + prefix + "[" + key + "]=" + value : "" + key + "=" + value));
}
}
return _results;
})();
return pairs.join('&');
};
This will construct strings like so:
toParams({a: 'one', b: 'two', c: {x: 'eight', y: ['g','h','j'], z: {asdf: 'fdsa'}}})
"a=one&b=two&c[x]=eight&c[y][0]=g&c[y][1]=h&c[y][2]=j&c[y][z][asdf]=fdsa"
Solution 14 - Javascript
You can use jQuery's param method:
var obj = {
param1: 'something',
param2: 'somethingelse',
param3: 'another'
}
obj['param4'] = 'yetanother';
var str = jQuery.param(obj);
alert(str);
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
Solution 15 - Javascript
var str = '';
for( var name in obj ) {
str += (name + '=' + obj[name] + '&');
}
str = str.slice(0,-1);
Give this a shot.
Example: http://jsfiddle.net/T2UWT/
Solution 16 - Javascript
A functional approach.
var kvToParam = R.mapObjIndexed((val, key) => {
return '&' + key + '=' + encodeURIComponent(val);
});
var objToParams = R.compose(
R.replace(/^&/, '?'),
R.join(''),
R.values,
kvToParam
);
var o = {
username: 'sloughfeg9',
password: 'traveller'
};
console.log(objToParams(o));
<script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.22.1/ramda.min.js"></script>
Solution 17 - Javascript
This one-liner also handles nested objects and JSON.stringify them as needed:
let qs = Object.entries(obj).map(([k, v]) => `${k}=${encodeURIComponent(typeof (v) === "object" ? JSON.stringify(v) : v)}`).join('&')
Solution 18 - Javascript
Object.toparams = function ObjecttoParams(obj)
{
var p = [];
for (var key in obj)
{
p.push(key + '=' + encodeURIComponent(obj[key]));
}
return p.join('&');
};
Solution 19 - Javascript
I needed something that processes nested objects as well as arrays.
const Util = {
isArray: function(val) {
return Object.prototype.toString.call(val) === '[object Array]';
},
isNil: function(val) {
return val === null || Util.typeOf(val)
},
typeOf: function(val, type) {
return (type || 'undefined') === typeof val;
},
funEach: function(obj, fun) {
if (Util.isNil(obj))
return; // empty value
if (!Util.typeOf(obj, 'object'))
obj = [obj]; // Convert to array
if (Util.isArray(obj)) {
// Iterate over array
for (var i = 0, l = obj.length; i < l; i++)
fun.call(null, obj[i], i, obj);
} else {
// Iterate over object
for (var key in obj)
Object.prototype.hasOwnProperty.call(obj, key) && fun.call(null, obj[key], key, obj);
}
}
};
const serialize = (params) => {
let pair = [];
const encodeValue = v => {
if (Util.typeOf(v, 'object'))
v = JSON.stringify(v);
return encodeURIComponent(v);
};
Util.funEach(params, (val, key) => {
let isNil = Util.isNil(val);
if (!isNil && Util.isArray(val))
key = `${key}[]`;
else
val = [val];
Util.funEach(val, v => {
pair.push(`${key}=${isNil ? "" : encodeValue(v)}`);
});
});
return pair.join('&');
};
Usage:
serialize({
id: null,
lat: "27",
lng: "53",
polygon: ["27,53", "31,18", "22,62", "..."]
}); // "id=&lat=27&lng=53&polygon[]=27%2C53&polygon[]=31%2C18&polygon[]=22%2C62&polygon[]=..."
Solution 20 - Javascript
this method uses recursion to descend into object hierarchy and generate rails style params which rails interprets as embedded hashes. objToParams generates a query string with an extra ampersand on the end, and objToQuery removes the final amperseand.
function objToQuery(obj){
let str = objToParams(obj,'');
return str.slice(0, str.length);
}
function objToParams(obj, subobj){
let str = "";
for (let key in obj) {
if(typeof(obj[key]) === 'object') {
if(subobj){
str += objToParams(obj[key], `${subobj}[${key}]`);
} else {
str += objToParams(obj[key], `[${key}]`);
}
} else {
if(subobj){
str += `${key}${subobj}=${obj[key]}&`;
}else{
str += `${key}=${obj[key]}&`;
}
}
}
return str;
}
Solution 21 - Javascript
You could use npm lib query-string
const queryString = require('query-string');
querystring.stringify({ foo: 'bar', baz: ['qux', 'quux'], corge: '' });
// Returns 'foo=bar&baz=qux&baz=quux&corge='
Solution 22 - Javascript
const obj = { id: 1, name: 'Neel' };
let str = '';
str = Object.entries(obj).map(([key, val]) => `${key}=${val}`).join('&');
console.log(str);
Solution 23 - Javascript
We should also handle the cases when the value of any entry is undefined, that key should not be included in the serialized string.
const serialize = (obj) => {
return Object.entries(obj)
.filter(([, value]) => value)
.map(([key, value]) => `${key}=${encodeURIComponent(value)}`)
.join('&');
}
Solution 24 - Javascript
export const convertObjToUrlParams = (obj) =>
{
var paramString = '';
for (let key in obj)
{
if (obj[key] !== null && obj[key] !== undefined)
{
paramString += '&';
paramString += key + "=" + obj[key];
}
}
return paramString;
}
Output Ex: &firstName=NoDo&userId=2acf67ed-73c7-4707-9b49-17e78afce42e&email=[email protected]&phoneNumber=12345678&password=123456
Solution 25 - Javascript
try this... this is working for nested object also..
let my_obj = {'single':'this is single', 'nested':['child1','child2']};
((o)=>{ return Object.keys(o).map(function(key){ let ret=[]; if(Array.isArray(o[key])){ o[key].forEach((item)=>{ ret.push(`${key}[]=${encodeURIComponent(item)}`); }); }else{ ret.push(`${key}=${encodeURIComponent(o[key])}`); } return ret.join("&"); }).join("&"); })(my_obj);
Solution 26 - Javascript
With Axios and infinite depth:
<pre>
<style>
textarea {
width: 80%;
margin-bottom: 20px;
}
label {
font-size: 18px;
font-weight: bold;
}
</style>
<label>URI</label>
<textarea id="uri" rows="7"></textarea>
<label>All Defaults (Bonus): </label>
<textarea id="defaults" rows="20"></textarea>
</pre>
<script src="https://unpkg.com/axios/dist/axios.min.js"></script>
<script>
const instance = axios.create({
baseUrl: 'http://my-api-server',
url: '/user'
})
const uri = instance.getUri({
params: {
id: '1234',
favFruits: [
'banana',
'apple',
'strawberry'
],
carConfig: {
items: ['keys', 'laptop'],
type: 'sedan',
other: {
music: ['on', 'off', {
foo: 'bar'
}]
}
}
}
})
const defaults = JSON.stringify(instance.defaults, null, 2)
document.getElementById('uri').value = uri
document.getElementById('defaults').value = defaults
</script>
Good Luck...