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Create nested Javascript Object dynamically

I have got a . (dot) separated string, from which I want to create nested JSON object. The length of the string is not fixed. For example,
var string = 'a.b.c.d';
Then my JSON object should be as following:
a: {
b: {
c:{
d: {
//Some properties here.
}
}
}
}
I've tried following code:
var packageName = "a.b.c.d"
var splitted = packageName.split('.');
var json = {};
for(var i=0;i<splitted.length-1;i++){
json[splitted[i]] = splitted[i+1];
}
But this returns
{
a: 'b',
b: 'c',
c: 'd'
}
But this is not what I want. I've also searched on google and found similar questions, but no solutions answer my problem. For example this.

A good use case for reduce
packageName = "a.b.c.d";
initProps = {hi: 'there'};
obj = packageName.split('.').reduceRight((o, x) => ({[x]: o}), initProps);
console.log(JSON.stringify(obj))
If you find loops easier to work with, a loop could be written concisely as
result = {};
ptr = result;
for (let prop of packageName.split('.'))
ptr = ptr[prop] = {};

You need to create a new object each time and attribute it to the last object created. And it goes until splitted.length, not splitted.length - 1, because you're using <, not <=.
var packageName = "a.b.c.d";
var splitted = packageName.split('.');
var json = {};
var current = json;
for (var i = 0; i < splitted.length; i++) {
current[splitted[i]] = {};
current = current[splitted[i]];
}
console.log(json);

You may use the last splittted part as property for some payload.
I suggest to keep the object reference and use a temporary variable for aceessing an creating a new property, if necessary.
Please avoid the use of JSON for not stringified objects.
var packageName = "a.b.c.d",
splitted = packageName.split('.'),
result = {},
temp = result,
i;
for (i = 0; i < splitted.length - 1; i++) {
temp[splitted[i]] = temp[splitted[i]] || {};
temp = temp[splitted[i]];
}
temp[splitted[i]] = { some: 'data' };
console.log(result);

Mapping string with key-value pair to object

Given the following string with key-value pairs, how would you write a generic function to map it to an object?
At the moment, I am just splitting by : and ; to get the relevant data, but it doesn't seem like a clean approach.
This my code at the moment:
var pd = `id:S76519;sku:S76519;name:StarGazer 3000;model:ICC74`;
var tempPd = pd.split(';');
for (i = 1; i < tempPd.length; i++) {
var b = tempPd[i].split(':');
console.log(b[1]);
}

What about using reduce:
function objectify(str) {
return str.split(";").reduce(function (obj, item) {
var a = item.split(":");
obj[a[0]] = a[1];
return obj;
}, {});
}
var strObj = "id:S76519;sku:S76519;name:StarGazer 3000;model:ICC74";
console.log(objectify(strObj));
or:
function objectify(str){
return str.split(";").reduce((obj,item)=>{
var a = item.split(":");
obj[a[0]]=a[1];
return obj;
},{});
}
var strObj = "id:S76519;sku:S76519;name:StarGazer 3000;model:ICC74";
console.log(objectify(strObj));

How to recursively merge 2 javascript objects?

I have 2 objects that I need to merge and keep all properties in tact, tried with jQuery $.extend but I cant get it to work . I tried all posts with how to merge javascript objects but simply cant get this to work.
var thz_icon_source = {"Spinners":["spinnericon1","spinnericon2"],"Awesome":["awesomeicon1","awesomeicon2"]};
var fa_icon_source = {"Spinners":["faspinner1","faspinner2"],"Awesome":["faawesome1","faawesome2"]};
var new_source ={};
$.extend(new_source,fa_icon_source,thz_icon_source);
console.log(thz_icon_source);
console.log(fa_icon_source);
console.log(new_source);
desired output should be like
{
"Spinners":["faspinner1","faspinner2","spinnericon1","spinnericon2"],
"Awesome":["faawesome1","faawesome2","awesomeicon1","awesomeicon2"]
}
This post Merge two json/javascript arrays in to one array has a simple object mine is not same as that one.

Demo
function mergeJSON(json1,json2)
{
var result = json1 ;
for (var prop in json2)
{
if (json2.hasOwnProperty(prop))
{
result[prop] = result[prop].concat(json2[prop]);
}
}
return result;
}

$.extend merges in missing properties, it doesn't combine the properties that are in common. You need to write a loop.
var thz_icon_source = {
"Spinners": ["spinnericon1", "spinnericon2"],
"Awesome": ["awesomeicon1", "awesomeicon2"]
};
var fa_icon_source = {
"Spinners": ["faspinner1", "faspinner2"],
"Awesome": ["faawesome1", "faawesome2"]
};
var new_source = {};
// First add in the new elements from thz_icon_source
$.extend(new_source, fa_icon_source, thz_icon_source);
// Now merge the common elements
$.each(fa_icon_source, function(k, e) {
if (thz_icon_source.hasOwnProperty(k)) {
new_source[k] = e.concat(thz_icon_source[k]);
}
});
console.log(thz_icon_source);
console.log(fa_icon_source);
console.log(new_source);
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

You can use this prototype to merge 2 or more objects the way you want it:
Object.prototype.assignDeep = function() {
var self = this;
Object.keys(arguments).forEach(obj => {
Object.keys(self).forEach(val => {
if (arguments[obj].hasOwnProperty(val)) {
var tmp = arguments[obj][val] instanceof Array ? arguments[obj][val] : [arguments[obj][val]];
self[val] = self[val].concat(tmp);
}
});
});
return self;
}
var thz_icon_source = {"Spinners":["spinnericon1","spinnericon2"],"Awesome":["awesomeicon1","awesomeicon2"]};
var fa_icon_source = {"Spinners":["faspinner1","faspinner2"],"Awesome":["faawesome1","faawesome2"]};
var b = thz_icon_source.assignDeep(fa_icon_source);
console.log(b);

You should use a loops with .concat():
function objectConcatArrays(){
var a = arguments, o = {};
for(var i=0,l=a.length; i<l; i++){
for(var p in a[i]){
if(p in o){
o[p] = o[p].concat(a[i][p]);
}
else{
o[p] = a[i][p];
}
}
}
return o;
}
var thz_icon_source = {"Spinners":["spinnericon1","spinnericon2"],"Awesome":["awesomeicon1","awesomeicon2"]};
var fa_icon_source = {"Spinners":["faspinner1","faspinner2"],"Awesome":["faawesome1","faawesome2"]};
var res = objectConcatArrays(thz_icon_source, fa_icon_source);
console.log(res);
Each argument represents an Object of Arrays. Add more if you want.

Nest JSON from array

I am trying to achieve something which seemed very basic but is getting me mad over the last days.
I have a simple array : ["a","b","c","d","e"] and I want to turn it into a nested JSON like this:
{"a":{"b":{"c":{"d":{"e":""}}}}}
Looping over it, I ran in problems like "how do you save the last key to set it afterwards without erasing it" and so on.
Does anyone has an idea?

You might have had problems because you were looping in the wrong direction. Try to build the object from inside-out:
array.reduceRight(function(v, key) {
var o = {};
o[key] = v;
return o;
}, "")
or, with a loop:
var val = "";
for (var i=array.length; i--; )
var o = {};
o[array[i]] = val;
val = o;
}
return val;

Here's one way to do it, recursively:
function convertToNestedObject(arr) {
var result = {};
if (arr.length === 1) {
result[arr[0]] = '';
} else {
result[arr[0]] = convertToNestedObject(arr.slice(1, arr.length));
}
return result;
}
You could pass the start index in to the function instead of using slice and creating copies of the array:
function convertToNestedObject(arr, startIndex) {
var result = {};
if (arr.length - startIndex === 1) {
result[arr[startIndex]] = '';
} else {
result[arr[startIndex]] = convertToNestedObject(arr, startIndex + 1);
}
return result;
}
Example: http://jsfiddle.net/jwcxfaeb/1/

Put current element as key and empty object ({}) as value. Continue with newly inserted empty object.
function toNested(arr){
var nested = {};
var temp = nested;
for(var i=0; i<arr.length; i++){
temp[arr[i]] = {};
temp = temp[arr[i]];
}
return nested;
}

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;