retrieving the value of object using strings - javascript

Here I am in a situation where I have to work only with strings, and because of this I also have to retrieve the value of an object from strings, in short:
to retrieve the value from an object we write:
someObject.property1.name // for say
but in my case i want to retrieve value from an object using string, i.e
'someObject.property1.name' // for say
since I was not so confident that I could do this, so I preferred tho search on internet and the most suitable solution which I got was
#1
Object.byString = function(o, s) {
s = s.replace(/\[(\w+)\]/g, '.$1'); // convert indexes to properties
s = s.replace(/^\./, ''); // strip a leading dot
var a = s.split('.');
while (a.length) {
var n = a.shift();
if (n in o) {
o = o[n];
} else {
return;
}
}
return o;
}
from here
#2
var deep_value = function(obj, path){
for (var i=0, path=path.split('.'), len=path.length; i<len; i++){
obj = obj[path[i]];
};
return obj;
};
from here
but as I said they are the most suitable example because they all are taking one extra parameter i.e. obj, O and so on... which is creating trouble for me, so I tried to improve the above code in search 2 because it is compact, and that results in failure. That code is:
var obj = {
foo: { bar: 'baz' }
};
var deep_value = function(path){
var obj = path.split('.');
obj = obj[0];
for (var i=0, path=path.split('.'), len=path.length; i<len; i++){
obj = obj[path[i+1]];
};
return obj;
};
alert(deep_value('obj.foo.bar'));
(I edited in his code for just an experiment). the above code does not need obj which is a perfect code - if it worked - and don't see any mistake, then why this code is not working, what is the correct code?
JSFIDDLE
thanks in advance

There were a couple problems with your #3 option:
First obj = obj[0]; was just going to have obj === "obj" which isn't going to help you at all. You need to actually get window["obj"] to get the top level object.
Second, you were traversing the for loop one too many times and going off the end of the path array.
Making changes in both these areas will make it work if obj is at the top level scope:
var obj = {
foo: { bar: 'baz' }
};
var deep_value = function(path, baseObj){
baseObj = baseObj || window;
var obj = path.split('.');
obj = baseObj[obj[0]];
for (var i=1, path=path.split('.'), len=path.length; i<len; i++){
obj = obj[path[i]];
};
return obj;
};
alert(deep_value('obj.foo.bar'));
Working demo: http://jsfiddle.net/jfriend00/jGb5p/
Here's a bit of a cleaned-up version:
var obj = {
foo: { bar: 'baz' }
};
var deep_value = function(path, baseObj){
baseObj = baseObj || window;
var pieces = path.split('.');
// get root level object
var obj = baseObj[pieces[0]];
for (var i = 1, len = pieces.length; i < len; i++){
obj = obj[pieces[i]];
}
return obj;
};
console.log(deep_value('obj.foo.bar'));
Working demo: http://jsfiddle.net/jfriend00/7J4Jb/

This be expressed compactly using reduce:
function eval_dotted_path(path) {
return path.split('.').reduce(function(value, segment) {
return value && value[segment];
}, window);
}
This splits up the path into "segments" on the dots, then calls reduce to "loop" over the segments, finding the next value inside the object on each iteration. The first segment is found in the global namespace, aka "window".
The value && value[segment] ensures that if at any point the current value is null/undefined (because the segment property was not present), undefined/null is returned.
If instead you want to find the value indicated by the dotted path starting from a known object, you can tweak this as
function eval_dotted_path_from_object(object, path) {
return path.split('.').reduce(function(value, segment) {
return value && value[segment];
}, object);
}
after which you can redefine the initial function as
function eval_dotted_path(path) {
return eval_dotted_path_from_object(window, path);
}
If you're in an old environment without Array.prototype.reduce, consider using Underscore's _.reduce, or a polyfill; some frameworks may provide the polyfill for you.

Related

Js how to set an item at a nested index in an empty array [duplicate]

I hope someone can help me with this Javascript.
I have an Object called "Settings" and I would like to write a function that adds new settings to that object.
The new setting's name and value are provided as strings. The string giving the setting's name is then split by the underscores into an array. The new setting should get added to the existing "Settings" object by creating new nested objects with the names given by each part of the array, except the last part which should be a string giving the setting's value. I should then be able to refer to the setting and e.g. alert its value. I can do this in a static way like this...
var Settings = {};
var newSettingName = "Modules_Video_Plugin";
var newSettingValue = "JWPlayer";
var newSettingNameArray = newSettingName.split("_");
Settings[newSettingNameArray[0]] = {};
Settings[newSettingNameArray[0]][newSettingNameArray[1]] = {};
Settings[newSettingNameArray[0]][newSettingNameArray[1]][newSettingNameArray[2]] = newSettingValue;
alert(Settings.Modules.Mediaplayers.Video.Plugin);
... the part that creates the nested objects is doing this ...
Settings["Modules"] = {};
Settings["Modules"]["Video"] = {};
Settings["Modules"]["Video"]["Plugin"] = "JWPlayer";
However, as the number of parts that make up the setting name can vary, e.g. a newSettingName could be "Modules_Floorplan_Image_Src", I'd like to do this dynamically using a function such as...
createSetting (newSettingNameArray, newSettingValue);
function createSetting(setting, value) {
// code to create new setting goes here
}
Can anyone help me work out how to do this dynamically?
I presume there has to be a for...loop in there to itterate through the array, but I haven't been able to work out a way to create the nested objects.
If you've got this far thanks very much for taking the time to read even if you can't help.
Put in a function, short and fast (no recursion).
var createNestedObject = function( base, names ) {
for( var i = 0; i < names.length; i++ ) {
base = base[ names[i] ] = base[ names[i] ] || {};
}
};
// Usage:
createNestedObject( window, ["shapes", "triangle", "points"] );
// Now window.shapes.triangle.points is an empty object, ready to be used.
It skips already existing parts of the hierarchy. Useful if you are not sure whether the hierarchy was already created.
Or:
A fancier version where you can directly assign the value to the last object in the hierarchy, and you can chain function calls because it returns the last object.
// Function: createNestedObject( base, names[, value] )
// base: the object on which to create the hierarchy
// names: an array of strings contaning the names of the objects
// value (optional): if given, will be the last object in the hierarchy
// Returns: the last object in the hierarchy
var createNestedObject = function( base, names, value ) {
// If a value is given, remove the last name and keep it for later:
var lastName = arguments.length === 3 ? names.pop() : false;
// Walk the hierarchy, creating new objects where needed.
// If the lastName was removed, then the last object is not set yet:
for( var i = 0; i < names.length; i++ ) {
base = base[ names[i] ] = base[ names[i] ] || {};
}
// If a value was given, set it to the last name:
if( lastName ) base = base[ lastName ] = value;
// Return the last object in the hierarchy:
return base;
};
// Usages:
createNestedObject( window, ["shapes", "circle"] );
// Now window.shapes.circle is an empty object, ready to be used.
var obj = {}; // Works with any object other that window too
createNestedObject( obj, ["shapes", "rectangle", "width"], 300 );
// Now we have: obj.shapes.rectangle.width === 300
createNestedObject( obj, "shapes.rectangle.height".split('.'), 400 );
// Now we have: obj.shapes.rectangle.height === 400
Note: if your hierarchy needs to be built from values other that standard objects (ie. not {}), see also TimDog's answer below.
Edit: uses regular loops instead of for...in loops. It's safer in cases where a library modifies the Array prototype.
function assign(obj, keyPath, value) {
lastKeyIndex = keyPath.length-1;
for (var i = 0; i < lastKeyIndex; ++ i) {
key = keyPath[i];
if (!(key in obj)){
obj[key] = {}
}
obj = obj[key];
}
obj[keyPath[lastKeyIndex]] = value;
}
Usage:
var settings = {};
assign(settings, ['Modules', 'Video', 'Plugin'], 'JWPlayer');
My ES2015 solution. Keeps existing values.
const set = (obj, path, val) => {
const keys = path.split('.');
const lastKey = keys.pop();
const lastObj = keys.reduce((obj, key) =>
obj[key] = obj[key] || {},
obj);
lastObj[lastKey] = val;
};
Example:
const obj = {'a': {'prop': {'that': 'exists'}}};
set(obj, 'a.very.deep.prop', 'value');
console.log(JSON.stringify(obj));
// {"a":{"prop":{"that":"exists"},"very":{"deep":{"prop":"value"}}}}
Using ES6 is shorten. Set your path into an array.
first, you have to reverse the array, to start filling the object.
let obj = ['a','b','c'] // {a:{b:{c:{}}}
obj.reverse();
const nestedObject = obj.reduce((prev, current) => (
{[current]:{...prev}}
), {});
Another recursive solution:
var nest = function(obj, keys, v) {
if (keys.length === 1) {
obj[keys[0]] = v;
} else {
var key = keys.shift();
obj[key] = nest(typeof obj[key] === 'undefined' ? {} : obj[key], keys, v);
}
return obj;
};
Example usage:
var dog = {bark: {sound: 'bark!'}};
nest(dog, ['bark', 'loudness'], 66);
nest(dog, ['woff', 'sound'], 'woff!');
console.log(dog); // {bark: {loudness: 66, sound: "bark!"}, woff: {sound: "woff!"}}
I love this ES6 immutable way to set certain value on nested field:
const setValueToField = (fields, value) => {
const reducer = (acc, item, index, arr) => ({ [item]: index + 1 < arr.length ? acc : value });
return fields.reduceRight(reducer, {});
};
And then use it with creating your target object.
const targetObject = setValueToField(['one', 'two', 'three'], 'nice');
console.log(targetObject); // Output: { one: { two: { three: 'nice' } } }
Lodash has a _.set method to achieve this
let obj = {}
_.set(obj, ['a', 'b', 'c', 'd'], 'e')
or
_.set(obj, 'a.b.c.d', 'e')
// which generate the following object
{
"a": {
"b": {
"c": {
"d": "e"
}
}
}
}
Here is a simple tweak to jlgrall's answer that allows setting distinct values on each element in the nested hierarchy:
var createNestedObject = function( base, names, values ) {
for( var i in names ) base = base[ names[i] ] = base[ names[i] ] || (values[i] || {});
};
Hope it helps.
Here is a functional solution to dynamically create nested objects.
const nest = (path, obj) => {
const reversedPath = path.split('.').reverse();
const iter = ([head, ...tail], obj) => {
if (!head) {
return obj;
}
const newObj = {[head]: {...obj}};
return iter(tail, newObj);
}
return iter(reversedPath, obj);
}
Example:
const data = {prop: 'someData'};
const path = 'a.deep.path';
const result = nest(path, data);
console.log(JSON.stringify(result));
// {"a":{"deep":{"path":{"prop":"someData"}}}}
Inspired by ImmutableJS setIn method which will never mutate the original. This works with mixed array and object nested values.
function setIn(obj = {}, [prop, ...rest], value) {
const newObj = Array.isArray(obj) ? [...obj] : {...obj};
newObj[prop] = rest.length ? setIn(obj[prop], rest, value) : value;
return newObj;
}
var obj = {
a: {
b: {
c: [
{d: 5}
]
}
}
};
const newObj = setIn(obj, ["a", "b", "c", 0, "x"], "new");
//obj === {a: {b: {c: [{d: 5}]}}}
//newObj === {a: {b: {c: [{d: 5, x: "new"}]}}}
Appreciate that this question is mega old! But after coming across a need to do something like this in node, I made a module and published it to npm.
Nestob
var nestob = require('nestob');
//Create a new nestable object - instead of the standard js object ({})
var newNested = new nestob.Nestable();
//Set nested object properties without having to create the objects first!
newNested.setNested('biscuits.oblong.marmaduke', 'cheese');
newNested.setNested(['orange', 'tartan', 'pipedream'], { poppers: 'astray', numbers: [123,456,789]});
console.log(newNested, newNested.orange.tartan.pipedream);
//{ biscuits: { oblong: { marmaduke: 'cheese' } },
orange: { tartan: { pipedream: [Object] } } } { poppers: 'astray', numbers: [ 123, 456, 789 ] }
//Get nested object properties without having to worry about whether the objects exist
//Pass in a default value to be returned if desired
console.log(newNested.getNested('generic.yoghurt.asguard', 'autodrome'));
//autodrome
//You can also pass in an array containing the object keys
console.log(newNested.getNested(['chosp', 'umbridge', 'dollar'], 'symbols'));
//symbols
//You can also use nestob to modify objects not created using nestob
var normalObj = {};
nestob.setNested(normalObj, 'running.out.of', 'words');
console.log(normalObj);
//{ running: { out: { of: 'words' } } }
console.log(nestob.getNested(normalObj, 'random.things', 'indigo'));
//indigo
console.log(nestob.getNested(normalObj, 'improbable.apricots'));
//false
Inside your loop you can use lodash.set and will create the path for you:
...
const set = require('lodash.set');
const p = {};
const [type, lang, name] = f.split('.');
set(p, [lang, type, name], '');
console.log(p);
// { lang: { 'type': { 'name': '' }}}
try using recursive function:
function createSetting(setting, value, index) {
if (typeof index !== 'number') {
index = 0;
}
if (index+1 == setting.length ) {
settings[setting[index]] = value;
}
else {
settings[setting[index]] = {};
createSetting(setting, value, ++index);
}
}
I think, this is shorter:
Settings = {};
newSettingName = "Modules_Floorplan_Image_Src";
newSettingValue = "JWPlayer";
newSettingNameArray = newSettingName.split("_");
a = Settings;
for (var i = 0 in newSettingNameArray) {
var x = newSettingNameArray[i];
a[x] = i == newSettingNameArray.length-1 ? newSettingValue : {};
a = a[x];
}
I found #jlgrall's answer was great but after simplifying it, it didn't work in Chrome. Here's my fixed should anyone want a lite version:
var callback = 'fn.item1.item2.callbackfunction',
cb = callback.split('.'),
baseObj = window;
function createNestedObject(base, items){
$.each(items, function(i, v){
base = base[v] = (base[v] || {});
});
}
callbackFunction = createNestedObject(baseObj, cb);
console.log(callbackFunction);
I hope this is useful and relevant. Sorry, I've just smashed this example out...
You can define your own Object methods; also I'm using underscore for brevity:
var _ = require('underscore');
// a fast get method for object, by specifying an address with depth
Object.prototype.pick = function(addr) {
if (!_.isArray(addr)) return this[addr]; // if isn't array, just get normally
var tmpo = this;
while (i = addr.shift())
tmpo = tmpo[i];
return tmpo;
};
// a fast set method for object, put value at obj[addr]
Object.prototype.put = function(addr, val) {
if (!_.isArray(addr)) this[addr] = val; // if isn't array, just set normally
this.pick(_.initial(addr))[_.last(addr)] = val;
};
Sample usage:
var obj = {
'foo': {
'bar': 0 }}
obj.pick('foo'); // returns { bar: 0 }
obj.pick(['foo','bar']); // returns 0
obj.put(['foo', 'bar'], -1) // obj becomes {'foo': {'bar': -1}}
A snippet for those who need to create a nested objects with support of array keys to set a value to the end of path. Path is the string like: modal.product.action.review.2.write.survey.data. Based on jlgrall version.
var updateStateQuery = function(state, path, value) {
var names = path.split('.');
for (var i = 0, len = names.length; i < len; i++) {
if (i == (len - 1)) {
state = state[names[i]] = state[names[i]] || value;
}
else if (parseInt(names[i+1]) >= 0) {
state = state[names[i]] = state[names[i]] || [];
}
else {
state = state[names[i]] = state[names[i]] || {};
}
}
};
Set Nested Data:
function setNestedData(root, path, value) {
var paths = path.split('.');
var last_index = paths.length - 1;
paths.forEach(function(key, index) {
if (!(key in root)) root[key] = {};
if (index==last_index) root[key] = value;
root = root[key];
});
return root;
}
var obj = {'existing': 'value'};
setNestedData(obj, 'animal.fish.pet', 'derp');
setNestedData(obj, 'animal.cat.pet', 'musubi');
console.log(JSON.stringify(obj));
// {"existing":"value","animal":{"fish":{"pet":"derp"},"cat":{"pet":"musubi"}}}
Get Nested Data:
function getNestedData(obj, path) {
var index = function(obj, i) { return obj && obj[i]; };
return path.split('.').reduce(index, obj);
}
getNestedData(obj, 'animal.cat.pet')
// "musubi"
getNestedData(obj, 'animal.dog.pet')
// undefined
Try this: https://github.com/silkyland/object-to-formdata
var obj2fd = require('obj2fd/es5').default
var fd = obj2fd({
a:1,
b:[
{c: 3},
{d: 4}
]
})
Result :
fd = [
a => 1,
b => [
c => 3,
d => 4
]
]
Here is a decomposition to several useful functions, that each preserve existing data. Does not handle arrays.
setDeep: Answers question. Non-destructive to other data in the object.
setDefaultDeep: Same, but only sets if not already set.
setDefault: Sets a key if not already set. Same as Python's setdefault.
setStructure: Helper function that builds the path.
// Create a nested structure of objects along path within obj. Only overwrites the final value.
let setDeep = (obj, path, value) =>
setStructure(obj, path.slice(0, -1))[path[path.length - 1]] = value
// Create a nested structure of objects along path within obj. Does not overwrite any value.
let setDefaultDeep = (obj, path, value) =>
setDefault(setStructure(obj, path.slice(0, -1)), path[path.length - 1], value)
// Set obj[key] to value if key is not in object, and return obj[key]
let setDefault = (obj, key, value) =>
obj[key] = key in obj ? obj[key] : value;
// Create a nested structure of objects along path within obj. Does not overwrite any value.
let setStructure = (obj, path) =>
path.reduce((obj, segment) => setDefault(obj, segment, {}), obj);
// EXAMPLES
let temp = {};
// returns the set value, similar to assignment
console.log('temp.a.b.c.d:',
setDeep(temp, ['a', 'b', 'c', 'd'], 'one'))
// not destructive to 'one'
setDeep(temp, ['a', 'b', 'z'], 'two')
// does not overwrite, returns previously set value
console.log('temp.a.b.z: ',
setDefaultDeep(temp, ['a', 'b', 'z'], 'unused'))
// creates new, returns current value
console.log('temp["a.1"]: ',
setDefault(temp, 'a.1', 'three'))
// can also be used as a getter
console.log("temp.x.y.z: ",
setStructure(temp, ['x', 'y', 'z']))
console.log("final object:", temp)
I'm not sure why anyone would want string paths:
They are ambiguous for keys with periods
You have to build the strings in the first place
Since I started with something from this page, I wanted to contribute back
Other examples overwrote the final node even if it was set, and that wasn't what I wanted.
Also, if returnObj is set to true, it returns the base object. By default, falsy, it returns the deepest node.
function param(obj, path, value, returnObj) {
if (typeof path == 'string') path = path.split(".");
var child = obj;
path.forEach((key, i) => {
if (!(key in child)) {
child[key] = (i < path.length-1) ? {} : value || {};
}
child = child[key];
});
return returnObj ? obj : child;
}
var x = {};
var xOut = param(x, "y.z", "setting")
console.log(xOut);
xOut = param(x, "y.z", "overwrite") // won't set
console.log(xOut);
xOut = param(x, "y.a", "setting2")
console.log(xOut);
xOut = param(x, "y.a", "setting2", true) // get object rather than deepest node.
console.log(xOut);
You can also do something where numeric keys are placed in arrays (if they don't already exist). Note that numeric keys won't convert to arrays for the first element of the path, since that's set by the type of your base-object.
function isNumber(n) {
return !isNaN(parseFloat(n)) && isFinite(n);
}
function param(obj, path, value, returnObj) {
if (typeof path == 'string') path = path.split(".");
var child = obj;
path.forEach((key, i) => {
var nextKey = path[i+1];
if (!(key in child)) {
child[key] = (nextKey == undefined && value != undefined
? value
: isNumber(nextKey)
? []
: {});
}
child = child[key];
});
return returnObj ? obj : child;
}
var x = {};
var xOut = param(x, "y.z", "setting")
console.log(xOut);
xOut = param(x, "y.z", "overwrite") // won't set
console.log(xOut);
xOut = param(x, "y.a", "setting2")
console.log(xOut);
xOut = param(x, "y.a", "setting2", true) // get object rather than deepest node.
xOut = param(x, "1.0.2.a", "setting")
xOut = param(x, "1.0.1.a", "try to override") // won't set
xOut = param(x, "1.0.5.a", "new-setting", true) // get object rather than deepest node.
console.log(xOut);
Naturally, when the numeric keys are greater than 0, you might see some undefined gaps.
Practical uses of this might be
function AddNote(book, page, line) {
// assume a global global notes collection
var myNotes = param(allNotes, [book, page, line], []);
myNotes.push('This was a great twist!')
return myNotes;
}
var allNotes = {}
var youthfulHopes = AddNote('A Game of Thrones', 4, 2, "I'm already hooked, at least I won't have to wait long for the books to come out!");
console.log(allNotes)
// {"A Game of Thrones": [undefined, undefined, undefined, undefined, [undefined, undefined, ["I'm already hooked, at least I won't have to wait long for the books to come out!"]]]}
console.log(youthfulHopes)
// ["I'm already hooked, at least I won't have to wait long for the books to come out!"]
function initPath(obj, path) {
path.split('.').reduce((o, key) => (
Object.assign(o, {[key]: Object(o[key])}),
o[key]
), obj);
return obj;
}
Usage
const obj = { a: { b: 'value1' } };
initPath(obj, 'a.c.d').a.c.d='value2';
/*
{
"a": {
"b": "value1",
"c": {
"d": "value2"
}
}
}
*/
simple answer. on es6, im using this
const assign = (obj, path, value) => {
let keyPath = path.split('.')
let lastKeyIndex = keyPath.length - 1
for (let i = 0; i < lastKeyIndex; ++i) {
let key = keyPath[i]
if (!(key in obj)) {
obj[key] = {}
}
obj = obj[key]
}
obj[keyPath[lastKeyIndex]] = value
}
example json
const obj = {
b: 'hello'
}
you can add new key
assign(obj, 'c.d.e', 'this value')
and you get like bellow
console.log(obj)
//response example
obj = {
b: 'hello',
c: {
d: {
e: 'this value'
}
}
}
function createObj(keys, value) {
let obj = {}
let schema = obj
keys = keys.split('.')
for (let i = 0; i < keys.length - 1; i++) {
schema[keys[i]] = {}
schema = schema[keys[i]]
}
schema[keys.pop()] = value
return obj
}
let keys = 'value1.value2.value3'
let value = 'Hello'
let obj = createObj(keys, value)
Eval is probably overkill but the result is simple to visualize, with no nested loops or recursion.
function buildDir(obj, path){
var paths = path.split('_');
var final = paths.pop();
for (let i = 1; i <= paths.length; i++) {
var key = "obj['" + paths.slice(0, i).join("']['") + "']"
console.log(key)
eval(`${key} = {}`)
}
eval(`${key} = '${final}'`)
return obj
}
var newSettingName = "Modules_Video_Plugin_JWPlayer";
var Settings = buildDir( {}, newSettingName );
Basically you are progressively writing a string "obj['one']= {}", "obj['one']['two']"= {} and evaling it;

JavaScript--merge two array objects into one arr object then loop through each index/object

var arrObj1 = [{a:1},{b:2}, {c:3}]
var arrObj2 = [{operator: LESS THAN}, {operator:GREATER THAN}, {operator:"NOT EQUAL"}]
so I want to merge obj at arrObj2[0] into obj at arrObj1[0], arrObj2[1] into obj at arrObj1[1] and so forth...
//resultArrObj = [{a:1, operator: LESS THAN}, {b:2, operator:"GREATER THAN}];
After (or while merging) i need to loop through each object and return a new obj which will have the properties(field, input, operator) and push into array.
field = key from arrObj1 (a, b, c)
input = value from arrObj1(1,2,3)
operator = "operator" from arrObj 2.
// var endResult = [{field:a, input:1, operator: LESS THAN}, {field:b, input:2, operator:GREATER THAN}];
thanks!!
I believe this does what you are looking for. It assumes that you know your data and doesn't do any error checking but just combines them the way that you asked.
var arrObj1 = [{a:1},{b:2}, {c:3}];
var arrObj2 = [{operator: "LESS THAN"}, {operator:"GREATER THAN"}, {operator:"NOT EQUAL"}];
var endResult = [];
var counter = 0;
var objNew = {};
arrObj1.forEach(function(fieldInput){
for ( field in fieldInput ){
objNew.field=field;
objNew.input=fieldInput[field];
objNew.operator=arrObj2[counter]['operator'];
counter++;
endResult.push(objNew);
objNew={};
};
})
// var endResult = [{field:a, input:1, operator: LESS THAN}, {field:b, input:2, operator:GREATER THAN}, {field:c, input:3, operator:NOT EQUAL}]
Let's break this problem into 2 steps:
1) Merging objects
2) Processing objects
We can write a generalized merging function:
if (!Object.prototype.extend) {
Object.prototype.extend = function (object) {
for (key in object) {
if (typeof object[key] === 'object' &&
typeof this[key] === 'object' &&
this.hasOwnProperty(key)) {
this[key].extend(object[key]);
} else {
this[key] = object[key];
}
}
return this;
};
};
The code above creates a method that all Objects share. It works like this:
var obj1 = { 'a': 7 },
obj2 = { 'b': 2 };
obj1.extend(obj2);
console.log(obj1); // { 'a': 7, 'b': 2 };
I usually wouldn't modify Objects like I have done with the .extend method, but it should be trivial to build something that does the same thing but has a different API. (for example, function extend (obj1, obj2) { do stuff.. and return extended object }
Anyways. That should solve the first part about merging objects.
The second part, processing this merged object, is simply using a for loop that iterates over the merged object, and pushes new objects into an array. It would look something like this:
for (var prop in mergedObject) {
var tempObject = {};
if (prop === 'operator') {
tempObject.operator = mergedObject.operator;
} else {
tempObject.field = prop;
tempObject.input = tempObject[prop];
}
endResult.push(tempObject);
}
Hopefully this helps you.

jQuery $.each with sorted object keys [duplicate]

Let's say I have a Javascript associative array (a.k.a. hash, a.k.a. dictionary):
var a = new Array();
a['b'] = 1;
a['z'] = 1;
a['a'] = 1;
How can I iterate over the keys in sorted order? If it helps simplify things, I don't even need the values (they're all just the number 1).
You can use the Object.keys built-in method:
var sorted_keys = Object.keys(a).sort()
(Note: this does not work in very old browsers not supporting EcmaScript5, notably IE6, 7 and 8. For detailed up-to-date statistics, see this table)
You cannot iterate over them directly, but you can find all the keys and then just sort them.
var a = new Array();
a['b'] = 1;
a['z'] = 1;
a['a'] = 1;
function keys(obj)
{
var keys = [];
for(var key in obj)
{
if(obj.hasOwnProperty(key))
{
keys.push(key);
}
}
return keys;
}
keys(a).sort(); // ["a", "b", "z"]
However there is no need to make the variable 'a' an array. You are really just using it as an object and should create it like this:
var a = {};
a["key"] = "value";
you could even prototype it onto object:
Object.prototype.iterateSorted = function(worker)
{
var keys = [];
for (var key in this)
{
if (this.hasOwnProperty(key))
keys.push(key);
}
keys.sort();
for (var i = 0; i < keys.length; i++)
{
worker(this[ keys[i] ]);
}
}
and the usage:
var myObj = { a:1, b:2 };
myObj.iterateSorted(function(value)
{
alert(value);
}
I agree with Swingley's answer, and I think it is an important point a lot of these more elaborate solutions are missing. If you are only concerned with the keys in the associative array and all the values are '1', then simply store the 'keys' as values in an array.
Instead of:
var a = { b:1, z:1, a:1 };
// relatively elaborate code to retrieve the keys and sort them
Use:
var a = [ 'b', 'z', 'a' ];
alert(a.sort());
The one drawback to this is that you can not determine whether a specific key is set as easily. See this answer to javascript function inArray for an answer to that problem. One issue with the solution presented is that a.hasValue('key') is going to be slightly slower than a['key']. That may or may not matter in your code.
There's no concise way to directly manipulate the "keys" of a Javascript object. It's not really designed for that. Do you have the freedom to put your data in something better than a regular object (or an Array, as your sample code suggests)?
If so, and if your question could be rephrased as "What dictionary-like object should I use if I want to iterate over the keys in sorted order?" then you might develop an object like this:
var a = {
keys : new Array(),
hash : new Object(),
set : function(key, value) {
if (typeof(this.hash[key]) == "undefined") { this.keys.push(key); }
this.hash[key] = value;
},
get : function(key) {
return this.hash[key];
},
getSortedKeys : function() {
this.keys.sort();
return this.keys;
}
};
// sample use
a.set('b',1);
a.set('z',1);
a.set('a',1);
var sortedKeys = a.getSortedKeys();
for (var i in sortedKeys) { print(sortedKeys[i]); }
If you have no control over the fact that the data is in a regular object, this utility would convert the regular object to your fully-functional dictionary:
a.importObject = function(object) {
for (var i in object) { this.set(i, object); }
};
This was a object definition (instead of a reusable constructor function) for simplicity; edit at will.
Get the keys in the first for loop, sort it, use the sorted result in the 2nd for loop.
var a = new Array();
a['b'] = 1;
a['z'] = 1;
a['a'] = 1;
var b = [];
for (k in a) b.push(k);
b.sort();
for (var i = 0; i < b.length; ++i) alert(b[i]);
You can use the keys function from the underscore.js library to get the keys, then the sort() array method to sort them:
var sortedKeys = _.keys(dict).sort();
The keys function in the underscore's source code:
// Retrieve the names of an object's properties.
// Delegates to **ECMAScript 5**'s native `Object.keys`
_.keys = nativeKeys || function(obj) {
if (obj !== Object(obj)) throw new TypeError('Invalid object');
var keys = [];
for (var key in obj) if (_.has(obj, key)) keys.push(key);
return keys;
};
// Shortcut function for checking if an object has a given property directly
// on itself (in other words, not on a prototype).
_.has = function(obj, key) {
return hasOwnProperty.call(obj, key);
};
<script type="text/javascript">
var a = {
b:1,
z:1,
a:1
}; // your JS Object
var keys = [];
for (key in a) {
keys.push(key);
}
keys.sort();
var i = 0;
var keyslen = keys.length;
var str = '';
//SORTED KEY ITERATION
while (i < keyslen) {
str += keys[i] + '=>' + a[keys[i]] + '\n';
++i;
}
alert(str);
/*RESULT:
a=>1
b=>1
z=>1
*/
</script>
var a = new Array();
a['b'] = 1;
a['z'] = 1;
a['a'] = 1;
var keys=Object.keys(a).sort();
for(var i=0,key=keys[0];i<keys.length;key=keys[++i]){
document.write(key+' : '+a[key]+'<br>');
}
I really like #luke-schafer's prototype idea, but also hear what he is saying about the issues with prototypes. What about using a simple function?
function sortKeysAndDo( obj, worker ) {
var keys = Object.keys(obj);
keys.sort();
for (var i = 0; i < keys.length; i++) {
worker(keys[i], obj[keys[i]]);
}
}
function show( key, value ) {
document.write( key + ' : ' + value +'<br>' );
}
var a = new Array();
a['b'] = 1;
a['z'] = 1;
a['a'] = 1;
sortKeysAndDo( a, show);
var my_object = { 'c': 3, 'a': 1, 'b': 2 };
sortKeysAndDo( my_object, show);
This seems to eliminate the issues with prototypes and still provide a sorted iterator for objects. I am not really a JavaScript guru, though, so I'd love to know if this solution has hidden flaws I missed.

Easy way to set javascript object multilevel property?

I am trying to create a javascript object like
var allUserExpiry={};
allUserExpiry[aData.userId][aData.courseId][aData.uscId] = aData;
But I am getting an error like allUserExpiry[aData.userId] undefined.
Is there a way, whereby I can set multi-level JS-Object keys? or is it important that I should go by doing allUserExpiry[aData.userId]={}, then allUserExpiry[aData.userId][aData.courseId]={} ?
Please let me know if there are any utility functions available for the same.
No, there is no way to set "multilevel keys". You need to initialize each object before trying to add properties to it.
var allUserExpiry = {};
allUserExpiry[aData.userId] = {}
allUserExpiry[aData.userId][aData.courseId] = {}
allUserExpiry[aData.userId][aData.courseId][aData.uscId] = aData;
Using Computed property names from ES6, it is possible to do:
var allUserExpiry = {
[aData.userId] = {
[aData.courseId]: {
[aData.uscId]: aData
}
}
};
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Object_initializer#Computed_property_names
Simply use loadash,
let object = {};
let property = "a.b.c";
let value = 1;
_.set(object, property, value); // sets property based on path
let value = _.get(object, property, default); // gets property based on path
Or you can do it:
function setByPath(obj, path, value) {
var parts = path.split('.');
var o = obj;
if (parts.length > 1) {
for (var i = 0; i < parts.length - 1; i++) {
if (!o[parts[i]])
o[parts[i]] = {};
o = o[parts[i]];
}
}
o[parts[parts.length - 1]] = value;
}
And use:
setByPath(obj, 'path.path2.path', someValue);
This approach has many weak places, but for fun... :)
Why not just do this?
var allUserExpiry={};
allUserExpiry[aData.userId] = {aData.courseId: {aData.uscId: aData}};
I have a pretty hacky but short way of doing it in IE9+ as well as real browsers.
Given var path = 'aaa.bbb.ccc.ddd.eee'; where path is what your intending to make into an object and var result = {}; will will create the object {aaa: {bbb: {ccc: {ddd: {eee: {}}}}}
result = {}
path.split('.').reduce(function(prev, e) {
var newObj = {};
prev[e] = newObj;
return newObj;
}, result);
will store the object in result.
How it works:
split('.') converts the input into ['aaa', 'bbb', 'ccc', 'ddd', 'eee']
reduce(function (...) {...}, result) runs through the array created by split, and for each entry will pass along a returned value to the next one. In our case we pass the new object through after adding the new object to the old one. This creates a chain of objects. reduce returns the last object you return inside of it, so we have to defined result beforehand.
This relies on using references so it won't be immediately clear how it works if you're expecting your code to be maintained by anyone else and should probably be avoided to be honest, but it works at least.
You can also use the following to create the initial structure:
var x = function(obj, keys) {
if (!obj) return;
var i, t;
for (i = 0; i < keys.length; i++) {
if (!t) {
t = obj[keys[i]] = {};
} else {
t[keys[i]] = {};
t = t[keys[i]];
}
}
};
var a = {};
x(a, ['A', 'B', 'C', 'D', 'E', 'F']);
Another approach without strings or array as argument.
function fillObject() {
var o = arguments[0];
for(var i = 1; i < arguments.length-1; i++) {
if(!o.hasOwnProperty(arguments[i])) {
o[arguments[i]] = {};
}
if(i < arguments.length-2) {
o = o[arguments[i]];
}else {
o[arguments[i]] = arguments[i+1]
}
}
}
var myObj = {"foo":{}};
fillObject(myObj,"back","to","the","future",2);
console.log(JSON.stringify(myObj));
// {"foo":{},"back":{"to":{"the":{"future":2}}}}
But I wouldn't use it :-) It's just for fun.
Because I don't like too much intelligent algorithm. (If it was in this category)
Using lodash you can do this easily (node exists and empty check for that node)..
var lodash = require('lodash-contrib');
function invalidateRequest(obj, param) {
var valid = true;
param.forEach(function(val) {
if(!lodash.hasPath(obj, val)) {
valid = false;
} else {
if(lodash.getPath(obj, val) == null || lodash.getPath(obj, val) == undefined || lodash.getPath(obj, val) == '') {
valid = false;
}
}
});
return valid;
}
Usage:
leaveDetails = {
"startDay": 1414998000000,
"endDay": 1415084400000,
"test": { "test1" : 1234 }
};
var validate;
validate = invalidateRequest(leaveDetails, ['startDay', 'endDay', 'test.test1']);
it will return boolean.
Another solution using reduce function (thanks Brian K).
Here we created a get/set to general proposes. The first function return the value in any level. The key is splited considering the separator. the function return the value refered from last index in the key's array
The second function will set the new value considering the last index of the splited key
the code:
function getObjectMultiLevelValue(_array,key,separator){
key = key.split(separator || '.');
var _value = JSON.parse(JSON.stringify(_array));
for(var ki in key){
_value = _value[key[ki]];
}
return _value;
}
function setObjectMultiLevelValue(_array,key,value,forcemode,separator){
key.split(separator || '.').reduce(function(prev, currKey, currIndex,keysArr) {
var newObj = {};
if(prev[currKey] && !forcemode){
newObj = prev[currKey];
}
if(keysArr[keysArr.length-1] == currKey){
newObj = value;
prev[currKey] = newObj;
}
prev[currKey] = newObj;
return newObj;
}, _array);
return _array;
}
//testing the function
//creating an array
var _someArray = {a:'a',b:'b',c:{c1:'c1',c2:{c21:'nothing here...'}}};
//a multilevel key to test
var _key = 'a,a1,a21';
//any value
var _value = 'new foo in a21 key forcing replace old path';
//here the new value will be inserted even if the path exists (forcemode=true). Using comma separator
setObjectMultiLevelValue(_someArray,_key,_value,true,',');
console.log('_someArray:');
console.log(JSON.stringify(_someArray));
//inserting another value in another key... using default separator
_key = 'c.c2.c21';
_value = 'new foo in c21 key';
setObjectMultiLevelValue(_someArray,_key,_value);
console.log('_someArray:');
console.log(JSON.stringify(_someArray));
//recovering the saved value with different separators
_key = 'a,a1,a21';
console.log(getObjectMultiLevelValue(_someArray,_key,','));
_key = 'c.c2.c21';
console.log(getObjectMultiLevelValue(_someArray,_key));
Let assume our object is
const data = {
//some other data
userInfo: {},
};
First, define a new property of that object
data.userInfo.vehicle = {};
then simply
data.userInfo.vehicle.vehicleType = state.userInfo.vehicleType;

The $.param( ) inverse function in JavaScript / jQuery

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" }
]

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