Related
I use the following function to dynamically check the properties of a variable number of objects.
// FUNCTION: Check Objects
var ObjectsN = 4;
function CheckObjects()
{
for (var i=0; i<=ObjectsN; i++)
{
if ((eval("Object"+i+".property")==0)
{
if (i==ObjectsN)
{
alert("Function finished");
}
}
else
{
return; // end function
}
}
}
I need to check if each object has the same property value.
Is there a way to do the same without using eval ?
A real example would be really much appreciated.
The structure you're looking for is an Array. So use an array to store your objects:
/* assuming `var Object1 = new Object(), Object2 = new Object();` and so on */
var objs = [ Object1, Object2, Object3 ];
Then testing for a property should implement hasOwnProperty while iterating:
for (var o = 0; i < objs.length; o++){
if (objs[o].hasOwnProperty('property')){
// Property exists, test its value:
}
}
You could then test against objs[o].property to retrieve its value and see if it matches what you're expecting.
And for those browsers that may not have the function available, here is a cross-browser version of hasOwnProperty (source, but originally from here):
/*
Cross-browser hasOwnProperty solution, based on answers from:
https://stackoverflow.com/questions/135448/how-do-i-check-to-see-if-an-object-has-an-attribute-in-javascript
*/
if ( !Object.prototype.hasOwnProperty ) {
Object.prototype.hasOwnProperty = function(prop) {
var proto = obj.__proto__ || obj.constructor.prototype;
return (prop in this) && (!(prop in proto) || proto[prop] !== this[prop]);
};
}
assuming Object0, Object1, Object2,Object3 & Object4 are global variables.
you could access the variables by using window
var ObjectsN = 4;
function CheckObjects()
{
for (var i=0; i<=ObjectsN; i++)
{
if (window['Object'+i].property == 0)
{
if (i==ObjectsN)
{
alert("Function finished");
}
}
else
{
return; // end function
}
}
}
Whenever you are thinking about numbering variables. Use an array instead.
Don't have Object1, Object2, etc. Have [ x, y, x ]
Then you can do:
for (var i = 0; i < objects.length; i++) {
var obj = objects[i];
if ("property" in obj) {
// Whatever
}
}
Similar to Neverever's answer, but passing a reference to the global object instead of assuming there's a window object available.
var ObjectsN = 4;
var CheckObjects = (function(global) {
for (var i=0; i<=ObjectsN; i++) {
if ( global['Object' + i].property == 0) {
if (i == ObjectsN) {
alert("Function finished");
}
} else {
return; // end function
}
}
}
Are you sure that == 0 is the test you want? That will return true even if the property doesn't exist. The function isn't particularly robust, if an object from 0 to n doesn't exist, an error will be thrown.
The function will continue only as long as Objectn.property == 0 returns true, so it will exit as soon as it gets a truethy result (e.g. Object0.property = 'foo').
This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
Dynamic object property name
I want to dynamically generate access to an object's property.
If I try to access mydata[i].val.name I get somename.
If I try it like mydata[i] + bar[j] (where bar[j] === '.val.name') it fails.
How do I dynamically create something like this? So that I can access any property of an object using a user generated value?
Some code:
If I have an object I want to be able to iterate through its properties, gathering the ones I am interested in. Ideally I would like something like the following:
var processData = function (data, keys, values) {
var returnData = [], i, j, k;
var parsedData = JSON.parse(data);
var keys = keys || null;
var values = values || null;
var datalen = parsedData.length;
for (i = 0; i < datalen; i++) {
returnData[i] = {};
for(j = 0; j< keys.length; j++){
for(k = 0; k < values.length; k++){
returnData[i][keys[j]] = parsedData[i] + values;
}
}
}
return returnData;
};
and then use it like:
var keys = ["foo","bar"];
var values = [".val.name", ".val.date"];
processData(data, keys, values);
But this does not work and in console I see foo="[object Object].val.name" rather than the expected foo="ACME Industries".
If you want to stick to your pattern of constructing the subscript as a string with dots in it you have to roll your own lookup function, like so:
function descend(object, sub) {
var handle = object,
stack = sub.split('.'),
history = [],
peek;
while (handle[stack[0]]) {
if (peek) {
history.push(peek);
}
peek = stack.shift();
handle = handle[peek];
}
if (stack.length > 0) {
history.push(peek);
throw "Traversal error, could not descend to '" + stack.join('.') + "' from '" + history.join('.') + "'.";
}
return handle;
}
var x = {
a: {
b: {
c: 15
},
d: 4
}
};
console.log(descend(x, "a"));
console.log(descend(x, "a.b"));
console.log(descend(x, "a.b.c"));
console.log(descend(x, "a.d"));
function processData(data, keys, values) {
if (keys.length !== values.length) {
throw "Mismatched keys and value lookups";
}
var i,
len = keys.length,
gathered = {},
k,
scratch,
v;
for (i = 0; i < len; i += 1) {
k = descend(data, keys[i]);
scratch = values[i].split('.');
scratch.shift();
v = descend(k, scratch.join('.'));
gathered[keys[i]] = v;
}
return gathered;
}
var data = {
foo: {
val: {
name: "ACME Industries"
}
},
bar: {
val: {
date: (new Date())
}
}
};
var keys = ["foo","bar"];
var values = [".val.name", ".val.date"];
processData(data, keys, values);
Please note: this will not be nearly as performant as coding without this style of lookup.
If you try:
new Object() + '.john.doe'
It will concatenate as a string, so you’ll get "[object Object].john.doe".
You should create a function that can handle dynamic property names instead (and there are plenty of those). You also might want to loose the ".foo.bar" syntax as a string (unless you plan to use eval()) and work solely with arrays instead.
If I understand correctly you need to use
mydata[i]["val"]["name"]
So, I'd use something like this:
var result =getItemByValuesPath(myData[i],values);
alert(result);
function getItemByValuesPath(item, values)
{
var result = item;
var vals = values.split(".");
for(var j=0; j<values.length; j++)
{
if(result==undefined)
{
return null;
}
result = result[values[j]];
}
}
i have this javascript var:
var mylist = '1,5,3,7,9,8,44,6';
I need to remove the 9, so that the final value is: 1,5,3,7,8,44,6
I usually do this server side with php (easy way). How can achieve this with javascript? A solution using jQuery would be even better.
considerations: it should work also if var is '99,9,96' or '9' or '99,9' or '9,98' ...etc.
my_list = my_list.split(',').filter(function(e) { return e != 9}).join(',');
Later edit: to support array.filter in IE:
//This prototype is provided by the Mozilla foundation and
//is distributed under the MIT license.
//http://www.ibiblio.org/pub/Linux/LICENSES/mit.license
if (!Array.prototype.filter)
{
Array.prototype.filter = function(fun)
{
var len = this.length;
if (typeof fun != "function")
throw new TypeError();
var res = new Array();
var thisp = arguments[1];
for (var i = 0; i < len; i++)
{
if (i in this)
{
var val = this[i]; // in case fun mutates this
if (fun.call(thisp, val, i, this))
res.push(val);
}
}
return res;
};
}
My suggestion:
var mylist = '1,5,3,7,9,8,44,6';
mylist = mylist.split(',').filter(function(elem, i) {
return elem !== '9';
}).join(',');
console.log(mylist); // = 1,5,3,7,8,44,6
Ref.: .filter()
filter():
Creates a new array with all elements
that pass the test implemented by the
provided function.
Do you know a JavaScript library that implements a generic Iterator class for collections (be it Arrays or some abstract Enumerable) with a full set of features, like the Google Common or the Apache Commons?
Edit: Enumerable#each is not an Iterator class. I'm looking for an Iterator, something that would let us write something like:
var iterator = new Iterator(myCollection);
for (var element = iterator.next(); iterator.hasNext(); element = iterator.next()) {
// iterator
}
Edit : mamoo reminded us of the Iterator implementation in Mozilla's Javascript 1.7. So the goal now is to find an implementation of this Iterator function in Javascript 1.5 (ECMA 4).
Edit2 : Why using an iterator when libraries (and ECMA 5) provide a each method? First, because each usually messes with this because the callback is call -ed (that's why each accepts a second argument in Prototype). Then, because people are much more familiar with the for(;;) construct than with the .each(callback) construct (at least, in my field). Lastly, because an iterator can iterate over plain objects (see JavaScript 1.7).
Edit3 : I accepted npup's anwser, but here is my shot at it :
function Iterator(o, keysOnly) {
if (!(this instanceof arguments.callee))
return new arguments.callee(o, keysOnly);
var index = 0, keys = [];
if (!o || typeof o != "object") return;
if ('splice' in o && 'join' in o) {
while(keys.length < o.length) keys.push(keys.length);
} else {
for (p in o) if (o.hasOwnProperty(p)) keys.push(p);
}
this.next = function next() {
if (index < keys.length) {
var key = keys[index++];
return keysOnly ? key : [key, o[key]];
} else throw { name: "StopIteration" };
};
this.hasNext = function hasNext() {
return index < keys.length;
};
}
var lang = { name: 'JavaScript', birthYear: 1995 };
var it = Iterator(lang);
while (it.hasNext()) {
alert(it.next());
}
//alert(it.next()); // A StopIteration exception is thrown
var langs = ['JavaScript', 'Python', 'C++'];
var it = Iterator(langs);
while (it.hasNext()) {
alert(it.next());
}
//alert(it.next()); // A StopIteration exception is thrown
Ok, the enumerable pattern is not a real iterator then.
Is this (below) useful for you? It conforms to the sematics you gave at least. As usual there are tradeoffs to be made here and there, and I didn't think very hard when deciding this time :).
And maybe you would like to be able to send in a number or two and iterate over a range in that way. But this could maybe be a start (there's support for iterating over hashes, arrays and strings).
It's a whole demo page which runs itself and does some debug output, but the (possibly) interesting stuff is in the
window.npup = (function() {
[...]
})();
spot.
Maybe it is just me who doesn't get it at all, but what would you use such a java-like Iterator for in a real situation?
Best
/npup
<html>
<head>
<title>untitled</title>
</head>
<body>
<ul id="output"></ul>
<script type="text/javascript">
window.log = (function (outputAreaId) {
var myConsole = document.getElementById(outputAreaId);
function createElem(color) {
var elem = document.createElement('li');
elem.style.color = color;
return elem;
}
function appendElem(elem) {
myConsole.appendChild(elem);
}
function debug(msg) {
var elem = createElem('#888');
elem.innerHTML = msg;
appendElem(elem);
}
function error(msg) {
var elem = createElem('#f88');
elem.innerHTML = msg;
appendElem(elem);
}
return {
debug: debug
, error: error
};
})('output');
window.npup = (function () {
// Array check as proposed by Mr. Crockford
function isArray(candidate) {
return candidate &&
typeof candidate==='object' &&
typeof candidate.length === 'number' &&
typeof candidate.splice === 'function' &&
!(candidate.propertyIsEnumerable('length'));
}
function dontIterate(collection) {
// put some checks chere for stuff that isn't iterable (yet)
return (!collection || typeof collection==='number' || typeof collection==='boolean');
}
function Iterator(collection) {
if (typeof collection==='string') {collection = collection.split('');}
if (dontIterate(collection)) {throw new Error('Oh you nasty man, I won\'t iterate over that ('+collection+')!');}
var arr = isArray(collection);
var idx = 0, top=0;
var keys = [], prop;
if (arr) {top = collection.length;}
else {for (prop in collection) {keys.push(prop);}}
this.next = function () {
if (!this.hasNext()) {throw new Error('Oh you nasty man. I have no more elements.');}
var elem = arr ? collection[idx] : {key:keys[idx], value:collection[keys[idx]]};
++idx;
return elem;
};
this.hasNext = function () {return arr ? idx<=top : idx<=keys.length;};
}
return {Iterator: Iterator};
})();
var element;
log.debug('--- Hash demo');
var o = {foo:1, bar:2, baz:3, bork:4, hepp: {a:1,b:2,c:3}, bluff:666, bluff2:777};
var iterator = new npup.Iterator(o);
for (element = iterator.next(); iterator.hasNext(); element = iterator.next()) {
log.debug('got elem from hash: '+element.key+' => '+element.value);
if (typeof element.value==='object') {
var i2 = new npup.Iterator(element.value);
for (var e2=i2.next(); i2.hasNext(); e2=i2.next()) {
log.debug(' # from inner hash: '+e2.key+' => '+e2.value);
}
}
}
log.debug('--- Array demo');
var a = [1,2,3,42,666,777];
iterator = new npup.Iterator(a);
for (element = iterator.next(); iterator.hasNext(); element = iterator.next()) {
log.debug('got elem from array: '+ element);
}
log.debug('--- String demo');
var s = 'First the pants, THEN the shoes!';
iterator = new npup.Iterator(s);
for (element = iterator.next(); iterator.hasNext(); element = iterator.next()) {
log.debug('got elem from string: '+ element);
}
log.debug('--- Emptiness demo');
try {
log.debug('Try to get next..');
var boogie = iterator.next();
}
catch(e) {
log.error('OW: '+e);
}
log.debug('--- Non iterables demo');
try{iterator = new npup.Iterator(true);} catch(e) {log.error('iterate over boolean: '+e);}
try{iterator = new npup.Iterator(6);} catch(e) {log.error('iterate over number: '+e);}
try{iterator = new npup.Iterator(null);} catch(e) {log.error('iterate over null: '+e);}
try{iterator = new npup.Iterator();} catch(e) {log.error('iterate over undefined: '+e);}
</script>
</body>
</html>
JQuery has the each() method:
http://api.jquery.com/jQuery.each/
but probably there's something similar even in other libraries such as Moo or Dojo.
Javascript 1.7 implements the Iterator function:
https://developer.mozilla.org/en/Core_JavaScript_1.5_Guide/Iterators_and_Generators
This is my attempt (jsfiddle) for ECMAScript 262 5th edition (aka Javascript). (Uses for example Object.keys and Array.isArray)
//Usage
b=Iterator(a);
while(b()){
console.log(b.value);
}
The code:
function Iterator(input,keys) {
// Input:
// input : object|array
// keys : array|undefined|boolean
function my() {
++my.index;
if (my.index >= my.keys.length) {
my.index = my.keys.length -1;
my.key = my.value = undefined;
return false;
}
my.key = my.useIndex ? my.index : my.keys[my.index];
my.value = my.input[my.key];
return my.index < my.keys.length;
}
if (input === null || typeof input !== 'object') {
throw new TypeError("'input' should be object|array");
}
if (
!Array.isArray(keys)
&& (typeof keys !== 'undefined')
&& (typeof keys !== 'boolean')
) {
throw new TypeError("'keys' should be array|boolean|undefined");
}
// Save a reference to the input object.
my.input = input;
if (Array.isArray(input)) {
//If the input is an array, set 'useIndex' to true if
//the internal index should be used as a key.
my.useIndex = !keys;
//Either create and use a list of own properties,
// or use the supplied keys
// or at last resort use the input (since useIndex is true in that
// case it is only used for the length)
my.keys = keys===true ? Object.keys(input) : keys || input;
} else {
my.useIndex = false;
my.keys = Array.isArray(keys) ? keys : Object.keys(input);
}
// Set index to before the first element.
my.index = -1;
return my;
}
Examples:
function Person(firstname, lastname, domain) {
this.firstname = firstname;
this.lastname = lastname;
this.domain = domain;
}
Person.prototype.type = 'Brillant';
var list = [
new Person('Paula','Bean','some.domain.name'),
new Person('John','Doe','another.domain.name'),
new Person('Johanna','Doe','yet.another.domain.name'),
];
var a,b;
var data_array = ['A','B','C','D','E','F'];
data_array[10]="Sparse";
console.log('Iterate over own keys in an object, unknown order');
a = Iterator(list[0]);
while(a()) console.log(" ",a.key, a.value);
console.log('Iterate over keys from anywhere, in specified order');
a = Iterator(list[0], ['lastname','firstname','type']);
while(a()) console.log(" ",a.key, a.value);
console.log('Iterate over all values in an array');
a = Iterator(list);
while(a()) console.log(a.key, a.value.firstname, a.value.lastname);
//Some abusing, that works for arrays (if the iterator.keys is modified
//it can also be used for objects)
console.log('Add more entries to the array, reusing the iterator...');
list.push(new Person('Another','Name','m.nu'));
while(a()) console.log(a.key, a.value.firstname, a.value.lastname);
console.log('Reset index and print everything again...');
a.index=-1; //Reset the index.
while(a()) console.log(a.key, a.value.firstname, a.value.lastname);
//With arrays, if setting 'keys' to true it will only print the
//elements that has values (If the array has more own enumerable values
//they too will be included)
console.log('Print sparce arrays...');
a = Iterator(data_array,true);
while(a()) console.log(a.key, a.value);
In the time since this question was asked JavaScript has added actual Iterators. Some built-in types, such as Array, Map, and String now have a default iteration behavior, but you can add your own to any object by including a next() function which returns one of two objects:
{done:true} /*or*/
{done:false, value:SOMEVALUE}
One way to access an object Iterator is with the:
for ( var of object ) { }
loop. Here is a (reasonably silly) example where we define an Iterator and then use it in such a loop to produce a string 1, 2, 3:
"use strict";
function count ( i ) {
let n = 0;
let I = {};
I[Symbol.iterator] = function() {
return { next: function() { return (n > i) ? {done:true}
: {done:false, value:n++} } } };
let s = "";
let c = "";
for ( let i of I ) { /* use the iterator we defined above */
s += c + i;
c = ", "
}
return s;
}
let s = count(3);
console.log(s);
Ive used LINQ to Javascript in a few projects.
http://jslinq.codeplex.com/Wikipage
var myList = [
{FirstName:"Chris",LastName:"Pearson"},
{FirstName:"Kate",LastName:"Johnson"},
{FirstName:"Josh",LastName:"Sutherland"},
{FirstName:"John",LastName:"Ronald"},
{FirstName:"Steve",LastName:"Pinkerton"}
];
var exampleArray = JSLINQ(myList)
.Where(function(item){ return item.FirstName == "Chris"; })
.OrderBy(function(item) { return item.FirstName; })
.Select(function(item){ return item.FirstName; });
I'm still a learner of js.class.
Though being close to Ruby, helps me.
http://jsclass.jcoglan.com/enumerable.html
MarkT
Since this hasn't been mention yet arrays have higher-order functions built in.
Map works like iterator that can only do a single pass.
[1,2,3,4,5].map( function(input){ console.log(input); } );
This code passes each element in the list into a function, in this case its a simple printer.
1
2
3
4
5
Given the following form:
<form>
<input name="foo" value="bar">
<input name="hello" value="hello world">
</form>
I can use the $.param( .. ) construct to serialize the form:
$.param( $('form input') )
=> foo=bar&hello=hello+world
How can I deserialize the above String with JavaScript and get a hash back?
For example,
$.magicFunction("foo=bar&hello=hello+world")
=> {'foo' : 'bar', 'hello' : 'hello world'}
Reference: jQuery.param( obj ).
You should use jQuery BBQ's deparam function. It's well-tested and documented.
This is a slightly modified version of a function I wrote a while ago to do something similar.
var QueryStringToHash = function QueryStringToHash (query) {
var query_string = {};
var vars = query.split("&");
for (var i=0;i<vars.length;i++) {
var pair = vars[i].split("=");
pair[0] = decodeURIComponent(pair[0]);
pair[1] = decodeURIComponent(pair[1]);
// If first entry with this name
if (typeof query_string[pair[0]] === "undefined") {
query_string[pair[0]] = pair[1];
// If second entry with this name
} else if (typeof query_string[pair[0]] === "string") {
var arr = [ query_string[pair[0]], pair[1] ];
query_string[pair[0]] = arr;
// If third or later entry with this name
} else {
query_string[pair[0]].push(pair[1]);
}
}
return query_string;
};
How about this short functional approach?
function parseParams(str) {
return str.split('&').reduce(function (params, param) {
var paramSplit = param.split('=').map(function (value) {
return decodeURIComponent(value.replace(/\+/g, ' '));
});
params[paramSplit[0]] = paramSplit[1];
return params;
}, {});
}
Example:
parseParams("this=is&just=an&example") // Object {this: "is", just: "an", example: undefined}
My answer:
function(query){
var setValue = function(root, path, value){
if(path.length > 1){
var dir = path.shift();
if( typeof root[dir] == 'undefined' ){
root[dir] = path[0] == '' ? [] : {};
}
arguments.callee(root[dir], path, value);
}else{
if( root instanceof Array ){
root.push(value);
}else{
root[path] = value;
}
}
};
var nvp = query.split('&');
var data = {};
for( var i = 0 ; i < nvp.length ; i++ ){
var pair = nvp[i].split('=');
var name = decodeURIComponent(pair[0]);
var value = decodeURIComponent(pair[1]);
var path = name.match(/(^[^\[]+)(\[.*\]$)?/);
var first = path[1];
if(path[2]){
//case of 'array[level1]' || 'array[level1][level2]'
path = path[2].match(/(?=\[(.*)\]$)/)[1].split('][')
}else{
//case of 'name'
path = [];
}
path.unshift(first);
setValue(data, path, value);
}
return data;
}
I am using David Dorward's answer, and realized that it doesn't behave like PHP or Ruby on Rails how they parse the params:
1) a variable is only an array if it ends with [], such as ?choice[]=1&choice[]=12, not when it is ?a=1&a=2
2) when mulitple params exist with the same name, the later ones replaces the earlier ones, as on PHP servers (Ruby on Rails keep the first one and ignore the later ones), such as ?a=1&b=2&a=3
So modifying David's version, I have:
function QueryStringToHash(query) {
if (query == '') return null;
var hash = {};
var vars = query.split("&");
for (var i = 0; i < vars.length; i++) {
var pair = vars[i].split("=");
var k = decodeURIComponent(pair[0]);
var v = decodeURIComponent(pair[1]);
// If it is the first entry with this name
if (typeof hash[k] === "undefined") {
if (k.substr(k.length-2) != '[]') // not end with []. cannot use negative index as IE doesn't understand it
hash[k] = v;
else
hash[k.substr(0, k.length-2)] = [v];
// If subsequent entry with this name and not array
} else if (typeof hash[k] === "string") {
hash[k] = v; // replace it
// If subsequent entry with this name and is array
} else {
hash[k.substr(0, k.length-2)].push(v);
}
}
return hash;
};
which is tested fairly thoroughly.
I know this is an old thread, but maybe there is still some relevance in it?
Inspired by Jacky Li's good solution I tried a slight variation of my own with the objective to also be able to take care of arbitrary combinations of arrays and objects as input. I looked at how PHP would have done it and tried to get something "similar" going. Here is my code:
function getargs(str){
var ret={};
function build(urlnam,urlval,obj){ // extend the return object ...
var i,k,o=obj, x, rx=/\[([^\]]*)\]/g, idx=[urlnam.replace(rx,'')];
while (x=rx.exec(urlnam)) idx.push(x[1]);
while(true){
k=idx.shift();
if(k.trim()=='') {// key is empty: autoincremented index
if (o.constructor.name=='Array') k=o.length; // for Array
else if (o===obj ) {k=null} // for first level property name
else {k=-1; // for Object
for(i in o) if (+i>k) k=+i;
k++;
}
}
if(idx.length) {
// set up an array if the next key (idx[0]) appears to be
// numeric or empty, otherwise set up an object:
if (o[k]==null || typeof o[k]!='object') o[k]=isNaN(idx[0])?{}:[];
o=o[k]; // move on to the next level
}
else { // OK, time to store the urlval in its chosen place ...
// console.log('key',k,'val',urlval);
o[k]=urlval===""?null:urlval; break; // ... and leave the while loop.
}
}
return obj;
}
// ncnvt: is a flag that governs the conversion of
// numeric strings into numbers
var ncnvt=true,i,k,p,v,argarr=[],
ar=(str||window.location.search.substring(1)).split("&"),
l=ar.length;
for (i=0;i<l;i++) {if (ar[i]==="") continue;
p=ar[i].split("=");k=decodeURIComponent(p[0]);
v=p[1];v=(v!=null)?decodeURIComponent(v.replace(/\+/g,'%20')):'';
if (ncnvt && v.trim()>"" && !isNaN(v)) v-=0;
argarr.push([k,v]); // array: key-value-pairs of all arguments
}
for (i=0,l=argarr.length;i<l;i++) build(argarr[i][0],argarr[i][1],ret);
return ret;
}
If the function is called without the str-argument it will assume window.location.search.slice(1) as input.
Some examples:
['a=1&a=2', // 1
'x[y][0][z][]=1', // 2
'hello=[%22world%22]&world=hello', // 3
'a=1&a=2&&b&c=3&d=&=e&', // 4
'fld[2][]=2&fld[][]=3&fld[3][]=4&fld[]=bb&fld[]=cc', // 5
$.param({a:[[1,2],[3,4],{aa:'one',bb:'two'},[5,6]]}), // 6
'a[]=hi&a[]=2&a[3][]=7&a[3][]=99&a[]=13',// 7
'a[x]=hi&a[]=2&a[3][]=7&a[3][]=99&a[]=13'// 8
].map(function(v){return JSON.stringify(getargs(v));}).join('\n')
results in
{"a":2} // 1
{"x":{"y":[{"z":[1]}]}} // 2
{"hello":"[\"world\"]","world":"hello"} // 3
{"a":2,"b":null,"c":3,"d":null,"null":"e"} // 4 = { a: 2, b: null, c: 3, d: null, null: "e" }
{"fld":[null,null,[2],[3,4],"bb","cc"]} // 5
{"a":[[1,2],[3,4],{"aa":"one","bb":"two"},[5,6]]} // 6
{"a":["hi",2,null,[7,99],13]} // 7
{"a":{"0":2,"3":[7,99],"4":13,"x":"hi"}} // 8
Whereas Jacky Li's solution would produce the outer container for a as a plain object
{a:{"0":["1","2"],"1":["3","4"],"2":["5","6"]}} // 6: JackyLi's output
getargs() looks at the first given index for any level to determine whether this level will be an object (non-numeric index) or an array (numeric or empty), thus resulting in the output as shown in the listing bove (no. 6).
If the current object is an array then nulls get inserted wherever necessary to represent empty positions. Arrays are always consecutively numbered and 0-based).
Note, that in the example no. 8 the "autoincrement" for empty indices still works, even though we are dealing with an object now and not an array.
As far as I have tested it, my getargs() behaves pretty much identically to Chriss Roger's great jQuery $.deparam() plugin mentioned in the accepted answer. The main difference is that getargs runs without jQuery and that it does autoincrement in objects while $.deparam() will not do that:
JSON.stringify($.deparam('a[x]=hi&a[]=2&a[3][]=7&a[3][]=99&a[]=13').a);
results in
{"3":["7","99"],"x":"hi","undefined":"13"}
In $.deparam() the index [] is interpreted as an undefined instead of an autoincremented numerical index.
Here's how you could create a new jQuery function:
jQuery.unparam = function (value) {
var
// Object that holds names => values.
params = {},
// Get query string pieces (separated by &)
pieces = value.split('&'),
// Temporary variables used in loop.
pair, i, l;
// Loop through query string pieces and assign params.
for (i = 0, l = pieces.length; i < l; i++) {
pair = pieces[i].split('=', 2);
// Repeated parameters with the same name are overwritten. Parameters
// with no value get set to boolean true.
params[decodeURIComponent(pair[0])] = (pair.length == 2 ?
decodeURIComponent(pair[1].replace(/\+/g, ' ')) : true);
}
return params;
};
Thanks to him http://james.padolsey.com/javascript/parsing-urls-with-the-dom/
Pretty easy :D
function params_unserialize(p){
var ret = {},
seg = p.replace(/^\?/,'').split('&'),
len = seg.length, i = 0, s;
for (;i<len;i++) {
if (!seg[i]) { continue; }
s = seg[i].split('=');
ret[s[0]] = s[1];
}
return ret;}
This is really old question, but as i have coming - other people may coming to this post, and i want to a bit refresh this theme. Today no need to make custom solutions - there is URLSearchParams interface.
var paramsString = "q=URLUtils.searchParams&topic=api";
var searchParams = new URLSearchParams(paramsString);
//Iterate the search parameters.
for (let p of searchParams) {
console.log(p);
}
The only one limitation i know - this feature not supported in IE / Edge.
Here's my JavaScript implementation which I use in a server-side JScript ASP Classic page (demo):
// Transforms a query string in the form x[y][0][z][]=1 into {x:{y:[{z:[1]}]}}
function parseJQueryParams(p) {
var params = {};
var pairs = p.split('&');
for (var i=0; i<pairs.length; i++) {
var pair = pairs[i].split('=');
var indices = [];
var name = decodeURIComponent(pair[0]),
value = decodeURIComponent(pair[1]);
var name = name.replace(/\[([^\]]*)\]/g,
function(k, idx) { indices.push(idx); return ""; });
indices.unshift(name);
var o = params;
for (var j=0; j<indices.length-1; j++) {
var idx = indices[j];
var nextIdx = indices[j+1];
if (!o[idx]) {
if ((nextIdx == "") || (/^[0-9]+$/.test(nextIdx)))
o[idx] = [];
else
o[idx] = {};
}
o = o[idx];
}
idx = indices[indices.length-1];
if (idx == "") {
o.push(value);
}
else {
o[idx] = value;
}
}
return params;
}
I came up with this solution, which behaves like the .Net function HttpUtility.ParseQueryString.
In the result, the query string parameters are store in properties as lists of values, so that qsObj["param"] will be the same as calling GetValues("param") in .Net.
I hope you like it. JQuery not required.
var parseQueryString = function (querystring) {
var qsObj = new Object();
if (querystring) {
var parts = querystring.replace(/\?/, "").split("&");
var up = function (k, v) {
var a = qsObj[k];
if (typeof a == "undefined") {
qsObj[k] = [v];
}
else if (a instanceof Array) {
a.push(v);
}
};
for (var i in parts) {
var part = parts[i];
var kv = part.split('=');
if (kv.length == 1) {
var v = decodeURIComponent(kv[0] || "");
up(null, v);
}
else if (kv.length > 1) {
var k = decodeURIComponent(kv[0] || "");
var v = decodeURIComponent(kv[1] || "");
up(k, v);
}
}
}
return qsObj;
};
Here is how to use it:
var qsObj = parseQueryString("a=1&a=2&&b&c=3&d=&=e&");
To preview the result in the console juste type in:
JSON.stringify(qsObj)
Output:
"{"a":["1","2"],"null":["","b",""],"c":["3"],"d":[""],"":["e"]}"
There's a beautiful one-liner over at CSS-Tricks (original source from Nicholas Ortenzio):
function getQueryParameters(str) {
return (str || document.location.search).replace(/(^\?)/,'').split("&").map(function(n){return n = n.split("="),this[n[0]] = n[1],this}.bind({}))[0];
}
The really clever part is how it uses the anonymous function's this object, adding a key/value pair for each of the queries in the string. That said, there's some room for improvement. I've modified it a bit below, with the following changes:
Added handling of empty strings and non-string input.
Handled URI-encoded strings (%40->#, etc).
Removed the default use of document.location.search when the input was empty.
Changed the name, made it more readable, added comments.
function deparam(str) {
// Uses an empty 'this' to build up the results internally
function splitQuery(query) {
query = query.split('=').map(decodeURIComponent);
this[query[0]] = query[1];
return this;
}
// Catch bad input
if (!str || !(typeof str === 'string' || str instanceof String))
return {};
// Split the string, run splitQuery on each piece, and return 'this'
var queries = str.replace(/(^\?)/,'').split('&');
return queries.map(splitQuery.bind({}))[0];
}
use this :
// convert query string to json object
var queryString = "cat=3&sort=1&page=1";
queryString
.split("&")
.forEach((item) => {
const prop = item.split("=");
filter[prop[0]] = prop[1];
});
console.log(queryString);
This is my version in Coffeescript.
Also works for url like
http://localhost:4567/index.html?hello=[%22world%22]&world=hello#/home
getQueryString: (url)->
return null if typeof url isnt 'string' or url.indexOf("http") is -1
split = url.split "?"
return null if split.length < 2
path = split[1]
hash_pos = path.indexOf "#"
path = path[0...hash_pos] if hash_pos isnt -1
data = path.split "&"
ret = {}
for d in data
[name, val] = d.split "="
name = decodeURIComponent name
val = decodeURIComponent val
try
ret[name] = JSON.parse val
catch error
ret[name] = val
return ret
Here's a simple & compact one if you only want to quickly get the parameters from a GET request:
function httpGet() {
var a={},b,i,q=location.search.replace(/^\?/,"").split(/\&/);
for(i in q) if(q[i]) {b=q[i].split("=");if(b[0]) a[b[0]]=
decodeURIComponent(b[1]).replace(/\+/g," ");} return a;
}
It converts
something?aa=1&bb=2&cc=3
into an object like
{aa:1,bb:2,cc:3}
Creates a serialized representation of an array or object (can be used as URL query string for AJAX requests).
<button id='param'>GET</button>
<div id="show"></div>
<script>
$('#param').click(function () {
var personObj = new Object();
personObj.firstname = "vishal"
personObj.lastname = "pambhar";
document.getElementById('show').innerHTML=$.param(`personObj`));
});
</script>
output:firstname=vishal&lastname=pambhar
answers could use a bit of jQuery elegance:
(function($) {
var re = /([^&=]+)=?([^&]*)/g;
var decodeRE = /\+/g; // Regex for replacing addition symbol with a space
var decode = function (str) {return decodeURIComponent( str.replace(decodeRE, " ") );};
$.parseParams = function(query) {
var params = {}, e;
while ( e = re.exec(query) ) {
var k = decode( e[1] ), v = decode( e[2] );
if (k.substring(k.length - 2) === '[]') {
k = k.substring(0, k.length - 2);
(params[k] || (params[k] = [])).push(v);
}
else params[k] = v;
}
return params;
};
})(jQuery);
fork at https://gist.github.com/956897
You can use the function .serializeArray() (Link) of jQuery itself. This function returns an array of key-value pair. Result example:
[
{ name: "id", value: "1" },
{ name: "version", value: "100" }
]