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does javascript have something equivalent to Python's `id` function? [duplicate]

I need to do some experiment and I need to know some kind of unique identifier for objects in javascript, so I can see if they are the same. I don't want to use equality operators, I need something like the id() function in python.
Does something like this exist ?

Update My original answer below was written 6 years ago in a style befitting the times and my understanding. In response to some conversation in the comments, a more modern approach to this is as follows:
(function() {
if ( typeof Object.id != "undefined" ) return;
var id = 0;
Object.id = function(o) {
if ( typeof o.__uniqueid != "undefined" ) {
return o.__uniqueid;
}
Object.defineProperty(o, "__uniqueid", {
value: ++id,
enumerable: false,
// This could go either way, depending on your
// interpretation of what an "id" is
writable: false
});
return o.__uniqueid;
};
})();
var obj = { a: 1, b: 1 };
console.log(Object.id(obj));
console.log(Object.id([]));
console.log(Object.id({}));
console.log(Object.id(/./));
console.log(Object.id(function() {}));
for (var k in obj) {
if (obj.hasOwnProperty(k)) {
console.log(k);
}
}
// Logged keys are `a` and `b`
If you have archaic browser requirements, check here for browser compatibility for Object.defineProperty.
The original answer is kept below (instead of just in the change history) because I think the comparison is valuable.
You can give the following a spin. This also gives you the option to explicitly set an object's ID in its constructor or elsewhere.
(function() {
if ( typeof Object.prototype.uniqueId == "undefined" ) {
var id = 0;
Object.prototype.uniqueId = function() {
if ( typeof this.__uniqueid == "undefined" ) {
this.__uniqueid = ++id;
}
return this.__uniqueid;
};
}
})();
var obj1 = {};
var obj2 = new Object();
console.log(obj1.uniqueId());
console.log(obj2.uniqueId());
console.log([].uniqueId());
console.log({}.uniqueId());
console.log(/./.uniqueId());
console.log((function() {}).uniqueId());
Take care to make sure that whatever member you use to internally store the unique ID doesn't collide with another automatically created member name.

So far as my observation goes, any answer posted here can have unexpected side effects.
In ES2015-compatible enviroment, you can avoid any side effects by using WeakMap.
const id = (() => {
let currentId = 0;
const map = new WeakMap();
return (object) => {
if (!map.has(object)) {
map.set(object, ++currentId);
}
return map.get(object);
};
})();
id({}); //=> 1

Latest browsers provide a cleaner method for extending Object.prototype. This code will make the property hidden from property enumeration (for p in o)
For the browsers that implement defineProperty, you can implement uniqueId property like this:
(function() {
var id_counter = 1;
Object.defineProperty(Object.prototype, "__uniqueId", {
writable: true
});
Object.defineProperty(Object.prototype, "uniqueId", {
get: function() {
if (this.__uniqueId == undefined)
this.__uniqueId = id_counter++;
return this.__uniqueId;
}
});
}());
For details, see https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Object/defineProperty

Actually, you don't need to modify the object prototype and add a function there. The following should work well for your purpose.
var __next_objid=1;
function objectId(obj) {
if (obj==null) return null;
if (obj.__obj_id==null) obj.__obj_id=__next_objid++;
return obj.__obj_id;
}

For browsers implementing the Object.defineProperty() method, the code below generates and returns a function that you can bind to any object you own.
This approach has the advantage of not extending Object.prototype.
The code works by checking if the given object has a __objectID__ property, and by defining it as a hidden (non-enumerable) read-only property if not.
So it is safe against any attempt to change or redefine the read-only obj.__objectID__ property after it has been defined, and consistently throws a nice error instead of silently fail.
Finally, in the quite extreme case where some other code would already have defined __objectID__ on a given object, this value would simply be returned.
var getObjectID = (function () {
var id = 0; // Private ID counter
return function (obj) {
if(obj.hasOwnProperty("__objectID__")) {
return obj.__objectID__;
} else {
++id;
Object.defineProperty(obj, "__objectID__", {
/*
* Explicitly sets these two attribute values to false,
* although they are false by default.
*/
"configurable" : false,
"enumerable" : false,
/*
* This closure guarantees that different objects
* will not share the same id variable.
*/
"get" : (function (__objectID__) {
return function () { return __objectID__; };
})(id),
"set" : function () {
throw new Error("Sorry, but 'obj.__objectID__' is read-only!");
}
});
return obj.__objectID__;
}
};
})();

Typescript version of #justin answer, ES6 compatible, using Symbols to prevent any key collision and added into the global Object.id for convenience. Just copy paste the code below, or put it into an ObjecId.ts file you will import.
(enableObjectID)();
declare global {
interface ObjectConstructor {
id: (object: any) => number;
}
}
const uniqueId: symbol = Symbol('The unique id of an object');
export function enableObjectID(): void {
if (typeof Object['id'] !== 'undefined') {
return;
}
let id: number = 0;
Object['id'] = (object: any) => {
const hasUniqueId: boolean = !!object[uniqueId];
if (!hasUniqueId) {
object[uniqueId] = ++id;
}
return object[uniqueId];
};
}
Example of usage:
console.log(Object.id(myObject));

jQuery code uses it's own data() method as such id.
var id = $.data(object);
At the backstage method data creates a very special field in object called "jQuery" + now() put there next id of a stream of unique ids like
id = elem[ expando ] = ++uuid;
I'd suggest you use the same method as John Resig obviously knows all there is about JavaScript and his method is based on all that knowledge.

For the purpose of comparing two objects, the simplest way to do this would be to add a unique property to one of the objects at the time you need to compare the objects, check if the property exists in the other and then remove it again. This saves overriding prototypes.
function isSameObject(objectA, objectB) {
unique_ref = "unique_id_" + performance.now();
objectA[unique_ref] = true;
isSame = objectB.hasOwnProperty(unique_ref);
delete objectA[unique_ref];
return isSame;
}
object1 = {something:true};
object2 = {something:true};
object3 = object1;
console.log(isSameObject(object1, object2)); //false
console.log(isSameObject(object1, object3)); //true

I faced the same problem and here's the solution I implemented with ES6
code
let id = 0; // This is a kind of global variable accessible for every instance
class Animal {
constructor(name){
this.name = name;
this.id = id++;
}
foo(){}
// Executes some cool stuff
}
cat = new Animal("Catty");
console.log(cat.id) // 1

I've used code like this, which will cause Objects to stringify with unique strings:
Object.prototype.__defineGetter__('__id__', function () {
var gid = 0;
return function(){
var id = gid++;
this.__proto__ = {
__proto__: this.__proto__,
get __id__(){ return id }
};
return id;
}
}.call() );
Object.prototype.toString = function () {
return '[Object ' + this.__id__ + ']';
};
the __proto__ bits are to keep the __id__ getter from showing up in the object. this has been only tested in firefox.

Notwithstanding the advice not to modify Object.prototype, this can still be really useful for testing, within a limited scope. The author of the accepted answer changed it, but is still setting Object.id, which doesn't make sense to me. Here's a snippet that does the job:
// Generates a unique, read-only id for an object.
// The _uid is generated for the object the first time it's accessed.
(function() {
var id = 0;
Object.defineProperty(Object.prototype, '_uid', {
// The prototype getter sets up a property on the instance. Because
// the new instance-prop masks this one, we know this will only ever
// be called at most once for any given object.
get: function () {
Object.defineProperty(this, '_uid', {
value: id++,
writable: false,
enumerable: false,
});
return this._uid;
},
enumerable: false,
});
})();
function assert(p) { if (!p) throw Error('Not!'); }
var obj = {};
assert(obj._uid == 0);
assert({}._uid == 1);
assert([]._uid == 2);
assert(obj._uid == 0); // still

This one will calculate a HashCode for each object, optimized for string, number and virtually anything that has a getHashCode function. For the rest it assigns a new reference number.
(function() {
var __gRefID = 0;
window.getHashCode = function(ref)
{
if (ref == null) { throw Error("Unable to calculate HashCode on a null reference"); }
// already cached reference id
if (ref.hasOwnProperty("__refID")) { return ref["__refID"]; }
// numbers are already hashcodes
if (typeof ref === "number") { return ref; }
// strings are immutable, so we need to calculate this every time
if (typeof ref === "string")
{
var hash = 0, i, chr;
for (i = 0; i < ref.length; i++) {
chr = ref.charCodeAt(i);
hash = ((hash << 5) - hash) + chr;
hash |= 0;
}
return hash;
}
// virtual call
if (typeof ref.getHashCode === "function") { return ref.getHashCode(); }
// generate and return a new reference id
return (ref["__refID"] = "ref" + __gRefID++);
}
})();

If you came here because you deal with class instances like me you can use static vars/methods to reference instances by a custom unique id:
class Person {
constructor( name ) {
this.name = name;
this.id = Person.ix++;
Person.stack[ this.id ] = this;
}
}
Person.ix = 0;
Person.stack = {};
Person.byId = id => Person.stack[ id ];
let store = {};
store[ new Person( "joe" ).id ] = true;
store[ new Person( "tim" ).id ] = true;
for( let id in store ) {
console.log( Person.byId( id ).name );
}

Here's a variant of Justin Johnson's answer that provides a scalability benefit when you are creating billions of objects for which you want the ID.
Specifically, rather than solely using a 1-up counter (that might overflow the representational limits of Number, and can't be cycled without risking reusing an ID), we register the object and its newly generated ID with a FinalizationRegistry, such that, at some point after the object is garbage collected, the ID is returned to a freelist for reuse by a newly created object (Python's id function can also return the same ID for multiple objects, so long as the existence of the two objects does not overlap in time).
Limitations:
It only works on objects, not JS primitives (this is somewhat reasonable; unlike Python, where everything is an object, JS primitives typically aren't, and the id function logically only works on objects, since primitives need not "exist" in any reasonably identifiable way).
If the code creates (without discarding) billions of objects, asks for their IDs, then releases them all at once and never asks for an ID again, the recovered IDs in the freelist constitute a memory leak of sorts. Hopefully the JS optimizer stores them efficiently, so the cost remains a small fraction of what the objects themselves cost, but it's still a cost. In cases where objects with IDs are regularly created and destroyed, the wasted memory is roughly tied to the maximum number of such ID-ed objects in existence at any given point in time.
If those limitations aren't a problem though, this works fairly well. I modified the testing code a bit to hand control back to the event loop (and hopefully the garbage collector) now and again while creating 10M garbage objects to ID, and on my browser, nearly half the object IDs get reclaimed for reuse; the final loop making five objects and IDing them produces IDs just above 1M, when over 2M objects had IDs generated at some point. In a realistic scenario with meaningful code executing and real async usage I'd expect better results simply because there would be more opportunities for the finalization registry to perform cleanup.
async function sleep(ms) {
await _sleep(ms);
}
function _sleep(ms) {
return new Promise((resolve) => setTimeout(resolve, ms));
}
(function() {
if ( typeof Object.id != "undefined" ) return;
var freelist = []; // Stores previously used IDs for reuse when an object with
// an ID is garbage collected, so creating and dropping billions
// of objects doesn't consume all available IDs
const registry = new FinalizationRegistry((freeid) => {
freelist.push(freeid);
});
var id = 0;
Object.id = function(o) {
if ( typeof o.__uniqueid != "undefined" ) {
return o.__uniqueid;
}
Object.defineProperty(o, "__uniqueid", {
value: freelist.length ? freelist.pop() : ++id,
enumerable: false,
// This could go either way, depending on your
// interpretation of what an "id" is
writable: false
});
registry.register(o, o.__uniqueid); // Sometime after o is collected, its ID
// will be reclaimed for use by a new object
return o.__uniqueid;
};
})();
var obj = { a: 1, b: 1 };
console.log(Object.id(obj));
console.log(Object.id([]));
console.log(Object.id({}));
console.log(Object.id(/./));
var idsum = 0; // So we do something real to prevent optimizing out code
// Make a ton of temporary objects with IDs, handing control back to the event loop
// every once in a while to (hopefully) see some IDs returned to the pool
for (var i = 0; i < 1000000; ++i) {
idsum += Object.id({c: i});
}
sleep(10).then(() => {
console.log(Object.id(function() { console.log("Hey"); }));
for (var i = 1000000; i < 2000000; ++i) {
idsum += Object.id({c: i});
}
console.log(Object.id(function() { console.log("There"); }));
sleep(10).then(() => {
for (var i = 0; i < 5; ++i) {
console.log(Object.id([i]));
}
console.log(idsum);
});
});
for (var k in obj) {
if (obj.hasOwnProperty(k)) {
console.log(k);
}
}
// Logged keys are `a` and `b`

What is the most efficient way for checking if an object parameter has all require properties?

In javascript using an object parameter is my preferred way of working with functions. To check that a function has the required parameters I either (Solution 1) loop through all the object parameters properties and throw an error or (Solution 2) wait until a required property is needed and throw an error. Solution two seems efficient but I have to throws in multiple places in the function. Solution 1 seems pragmatic but should probably be a reusable piece of code. Is there another solution I should be looking at?

You can actually do this
var propsNeeded = ["prop1", "prop2", "blah", "blah", "blah"],
obj = {
prop1: "Hi"
}
function hasRequiredProperties(props, obj){
return Object.keys(obj).sort().join() == propsNeeded.sort().join();
}
console.log(hasRequiredProperties(propsNeeded, obj)); // false
You can check for single properties like
function hasProperty(propName, obj){
return obj.hasOwnProperty(propName);
}

For consistency I would create require method and use it always when some property is required.
var require = function (key, object) {
if (typeof object[key] === 'undefined') {
throw new Error('Required property ' + key + ' is undefined');
}
};
I would test if required property exists as soon as I'm certain that property is needed. Like this:
var example = function (args) {
require('alwaysRequired', args);
// some code here which uses property alwaysRequired
if (args.something) {
require('sometimesRequired', args);
// some code here which uses property sometimesRequired
}
};

Using #Amit's answer I'd probably add a method to Object itself:
Object.prototype.hasAllProperties = function(props, fire){
var result = Object.keys(this).sort().join() == propsNeeded.sort().join();
if (fire && !result){
throw new Error('Object does not define all properties');
}
return result;
}
and in your function:
function someFunction(myObject){
var objComplete = myObject.hasAllProperties(["prop1", "prop2", "prop3"], false);
}
Update:
After noticing the problem with #Amit's original answer, here's what I suggest:
Object.prototype.hasAllProperties = function(props, fire){
var result = true;
$(props).each(function(i, e){
if (!this.hasOwnProperty(e) ) {
result = false;
return false;
}
});
if (fire && !result){
throw new Error('Object does not define all properties');
}
return result;
}

This is just a general case of checking for presence of keys on a object, which can be done easily enough with
requiredParams.every(function(prop) { return prop in paramObj; })
It almost reads like natural language. "Taking the required parameters, is EVERY one of them IN the parameter object?".
Just wrap this in function checkParams(paramObj, requiredParams) for easy re-use.
More generally, this is the problem of asking if one list (in this case the list of required parameters) is included in another list (the keys on the params object). So we can write a general routine for list inclusion:
function listIncluded(list1, list2) {
return list1.every(function(e) { return list2.indexOf(e) !== -1; });
}
Then our parameter-checking becomes
function checkParams(paramObj, requiredParams) {
return listIncluded(requiredParams, Object.keys(paramObj));
}

If you want to know if object has at least some properties you can use this function without third parameter:
function hasRequiredProperties(propsNeeded, obj, strict) {
if (strict) return Object.keys(obj).sort().join() == propsNeeded.sort().join();
for (var i in propsNeeded ) {
if (!obj.hasOwnProperty(propsNeeded[i])) return false;
}
return true;
};
Example:
options = {url: {
protocol: 'https:',
hostname: 'encrypted.google.com',
port: '80'
}
};
propsNeeded = ['protocol', 'hostname'];
hasRequiredProperties(propsNeeded, options.url); // true
hasRequiredProperties(propsNeeded, options.url, true); // false

Why does my WinJS Grouped Binding List play musical chairs with some items?

I'm creating a grouped list of my pupils as per this example: http://msdn.microsoft.com/en-us/library/windows/apps/hh465464.aspx
The actual code for creating the grouping as well as the HTML are almost identical (safe for name changes).
I'm then push()ing some items into the original List() which then also updates the GroupedList(). That part works fine.
However, what I'm seeing is this:
This list should be grouped by firstnames (on display is "Lastname, Firstname"). What I'm seeing here is that item #1 should be in "S", #3 should be in "A" and #6 should be in "I".
The only thing that I'm doing different from the example is the DataSource, insofar as I'm push()ing an actual WinJS Class in there (with getter and setter functions for the attributes displayed in the List).
However, the getGroupKey(dataItem) and other grouping functions are working as they should, i.e. return the proper values.
Any ideas? Because otherwise I'd have to look at using two arrays (one being the List() and another the array where the class instances live) for which I'd then have to program sync routines to keep the data consistent and that's something I actually wanted to escape from...
Code follows below, relevant snippets only.
Defining the Lists and grouping functions:
function compareGroups(leftKey, rightKey) {
return leftKey.charCodeAt(0) - rightKey.charCodeAt(0);
}
function getGroupKey(dataItem) {
return dataItem.lastname.toUpperCase().charAt(0);
}
function getGroupData(dataItem) {
return {
title: dataItem.lastname.toUpperCase().charAt(0)
};
}
var pupilsList = new WinJS.Binding.List({ binding: true });
var groupedPupilsList = pupilsList.createGrouped(getGroupKey, getGroupData, compareGroups);
Where the Data comes from:
var Schueler = WinJS.Class.define(function (original, id, firstname, lastname, tutor_id, picture, email, phone, notes, birthday, classes) {
var that = this;
this._classnames = new Array();
if (original) {
[... irrelevant part snipped ...]
});
} else {
var row = id;
this._id = row.rowid;
this._firstname = row.firstname_enc;
this._lastname = row.lastname_enc;
this._tutor_id = row.tutor_id;
this._picture = row.picture_enc;
this._email = row.email_enc;
this._phone = row.phone_enc;
this._notes = row.notes_enc;
this._birthday = row.birthday_enc;
this._guid = row.guid;
this.updateClassnames();
}
},
{
id: {
get: function () {
return this._id;
},
set: function (id) {
this._id = id;
}
},
firstname: {
get: function () {
return this._firstname;
},
set: function () {
//TODO
}
},
lastname: {
get: function () {
return this._lastname;
},
set: function () {
//TODO
}
},
[... irrelevant parts snipped ...]
classnames: {
get: function () {
return this._classnames.join(", ");
},
set: function (names) {
this._classnames = names;
}
},
updateClassnames: function () {
var that = this;
SQLite3JS.openAsync(DataLayer.db_path)
.then(function (db) {
var sql = "SELECT Classes.name_enc FROM Classes JOIN Classes_Pupils ON Classes.rowid = Classes_Pupils.class_id JOIN Pupils ON Classes_Pupils.pupil_id = Pupils.rowid WHERE Pupils.rowid = {0};".format(that._id);
return db.allAsync(sql)
.then(function (results) {
db.close();
var names = new Array();
for (var i = 0; i < results.length; i++) {
names.push(results[i].name_enc.toString().decrypt());
}
that.classnames = names;
DataLayer.PupilsList.dispatchEvent("reload");
}, function (error) {
if (error.message.indexOf("database is locked") > -1) {
console.log("DB locked, will try again in 50 ms");
window.setTimeout(that.updateClassnames(), 50);
}
});
});
}
},
{
reconstructAll: function () {
DataLayer.retrieveSeveralRows("Pupils", function (results) {
for (var i = 0; i < results.length; i++) {
DataLayer.PupilsList.push(new Schueler(false, results[i]));
}
});
}
});
WinJS.Namespace.define("DataLayer", {
Schueler: Schueler
});
Workflow is as follows: First empty lists are created, then another routine checks for DB availability. As soon as that routine gives a green light, Schueler.reconstructAll() is called.
DataLayer.retrieveSeveralRows(table, callback) is a wrapper function for a call to the SQLite database, essentially doing a SELECT * FROM Pupils and returning the results to the callback function.
This callback then creates a new instance of the Schueler() class and pushes that to the list.
Addendum: If I use createSorted() everything is just dandy. Will use that for now.
Edit: As suggested by Kraig Brockschmidt, it seems to have indeed been a localization issues, so adding one line and modifying one function as follows fixes everything right up:
var charGroups = Windows.Globalization.Collation.CharacterGroupings();
function getGroupKey(dataItem) {
return charGroups.lookup(dataItem.lastname.toUpperCase().charAt(0));
}

I see that you're working with createSorted now, but there are a couple of other things you can do to diagnose the original issue.
First, try using some static data instead of populating your list dynamically.
Second, put some console.log output inside your getGroupKey and getGroupData functions so you can evaluate what you're returning, exactly.
The other thing I should mention is that the MSDN docs page shows code that isn't sensitive to all local languages. That is, using the first character of a string for sort order isn't always the right thing. There is an API in Windows.Globalization.Collation (http://msdn.microsoft.com/en-us/library/windows/apps/windows.globalization.collation.aspx) that is built to handle sort ordering properly. If you look at the [HTML ListView Grouping and Semantic Zoom sample][1], in the file groupeddata.js, you'll see how this is used. Offhand this shouldn't affect your data, but I wanted to mention it.

MVC4 ModelState property name to JSON or Array

I am using a complex object graph serialized to JSON with MVC4/jQuery/Sammy/Rivets for SPA functionality.
I have a object graph that looks a bit like this when serialized to JSON (obviously mocked-up):
model =
{
Name: "Me",
Age: 22,
Hobbies:
[
{ Name: "Biking", IsActive: true },
{ Name: "Programming", IsActive: true }
]
}
Everything works quite well until I need Unobtrusive validation, since my Hobbies are in a SlickGrid and I am managing all the data myself. To handle this I am returning my ModelState with my JSON next to my model.
return JSON(new { model = model, modelState = this.ModelState });
From there I intend to iterate through the modelState and assign errors to the right place with some custom function, but there is one problem.
ModelState looks like this:
"Name",
"Age",
"Hobbies[0].Name",
"Hobbies[0].IsActive",
"Hobbies[1].Name",
"Hobbies[1].IsActive"
I need to separate the [0]'s into an object and [1]'s into their own objects so I can smoothly get the values. This gets confusing for me when I begin to account for a third level of complex object array.
Solution:
var ModelStateConverter = function ($, module) {
module = module || {};
// Convert The ModelState form style object to a standard JS object structure.
module.toObject = function (modelState) {
var ModelState = {};
$.each(modelState, function (key, value) {
AssignValuesToObjectStore(key, ModelState, value);
});
return ModelState;
}
// item is the full identifier ex. "Hobbies[0].Name"
// store is the object we are going to throw arrays, objects, and values into.
// value is the error message we want to get in the right place.
// index is an internal processing parameter for arrays only, setting it's value has no effect.
function AssignValuesToObjectStore(item, store, value, index) {
var periodMatch = item.match(/[\.]/);
if (periodMatch === null) {
if (Array.isArray(store)) {
if (store[index] === undefined) {
store[index] = {};
}
store[index][item] = value;
}
else {
store[item] = value;
}
}
else {
// This wasn't a simple property or end of chain.
var currentProperty = item.slice(0, periodMatch.index); // Get our property name up to the first period.
var container = {}; // We assume we are dealing with an object unless proven to be an array.
var arrayIndex; // This is irrelevant unless we have an array.
if (currentProperty.slice(-1, currentProperty.length) === "]") {
// We are dealing with an array! Hoo Ray?!
arrayIndex = parseInt(currentProperty.slice(currentProperty.indexOf("[") + 1, currentProperty.indexOf("]")));
currentProperty = currentProperty.slice(0, currentProperty.indexOf("[")); // remove the indexer ex. [0] so we are left with the real name
container = []; // We know we need an array instead;
}
if (store[currentProperty] === undefined) {
store[currentProperty] = container; // If this property isn't already created, then do so now.
}
//Recurseive nature here.
AssignValuesToObjectStore(item.slice(periodMatch.index + 1, item.length), store[currentProperty], value, arrayIndex);
}
}
return module;
}($, ModelStateConverter);
You can call this from:
ModelStateConverter.toObject(data.modelState);
Where data.modelState is assumed to be the ModelState from the server.

You could try a library like JSON.NET, or the class JavaScriptSerializer, to serialize the ModelState.

How to clear JSON object using JavaScript or jQuery

I have a JSON object as follows. After sending ajax call I want to clear this. How I can do?
var cfamFwdDtls = {
cndtwizid: [],
clientIdsInstnIds: [],
positioncd: '',
positionCnt: '',
rcrtrInstnId: '',
positionLocation: {
cntryIdFrCndt: '',
stateIdFrCndt: '',
zipIdFrCndt: '',
cityIdFrCndt: ''
},
searchPstnSkill: []
};

If you want to reset the entire object, just reset the variable back to {};
cfamFwdDtls = {};
// or
cfamFwdDtls = new Object;
// will prevent garbage collection
delete cfamFwdDtls;
However, if you want a more fine-grained way of "resetting" the object, you are going to need to define what specifically your requirements for a reset are. Regardless, you can always iterate through the object and make the necessary objects.
for (var key in cfamFwdDtls) {
if (typeof cfamFwdDtls[key] == "string") {
cfamFwdDtls[key] = '';
} else if (Array.isArray(cfamFwdDtls[key])) {
cfamFwdDtls[key] = [];
} else {
delete cfamFwdDtls[key];
}
}
The above definition could be a possible way to define your particular situation since I only see strings and arrays in your object. If the key is neither of those, it would just delete the key. This could be tailored as you find necessary.

for (var entry in cfamFwdDtls) delete cfamFwdDtls[entry];
If you simply reassign to {}, you'll get in trouble if there are multiple references to your object. Also may face garbage collection issues.

there is alternative for this if you want to remove object.Something like this
delete cfamFwdDtls;
you can use delete keyword for deleting a object.
more details read
example

The Problems
When I ran into this I wanted to solve two issues.
Have one location for a complex structure definition.
Reassurance the entire definition is reset.
Solutions
The basic idea is have a function return the empty structure. If it is not in a function you could change the structure itself not the instance of the structure.
Examples
Class
I personally use this but I also include the API functions in the class and make it an HTTP service.
class complexStructure {
constructor () {
this.payload = resetPayload();
}
resetPayload () {
this.payload = {
cndtwizid: [],
clientIdsInstnIds: [],
//...
};
}
}
Function
function resetStructure () {
return {
cndtwizid: [],
clientIdsInstnIds: [],
//...
};
}
let resetStructure = resetStructure()

function getJson(){
return {
cndtwizid: [],
clientIdsInstnIds: [],
positioncd: '',
positionCnt: '',
rcrtrInstnId: '',
positionLocation: {
cntryIdFrCndt: '',
stateIdFrCndt: '',
zipIdFrCndt: '',
cityIdFrCndt: ''
},
searchPstnSkill: []
};
}
var data = getJson();
data.positioncd = 'xyz';
data.rcrtrInstnId = 'abc';
$.ajax(...){
}
success(response){
data = getJson(); //re-initialize structure
}