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How to remove character from left of the string until first : if found?

I have JSON String as the one below which is returned from the previous function. It is a string, not object.
{
"qs1": {
"mistake": [{
"id": 1,
"name": "Subject-Verb Agreement Errors."
}, {
"id": 1,
"name": "Sentence Fragments."
}, {
"id": 1,
"name": "Missing Comma After Introductory Element."
}]
}
}
I converted it into an object by using Jquery.parseJSON() now I want to use length to find a number of mistakes.
Problem:
the first key qs1 of the returned JSON can be different like qs2,qs3 & so on. I don't want to use a loop to get the key name qs1,qs2 because it will take a lot of time in only getting a key name and if I have a lot of questions. Also, I don't know the number of questions.
Is there is any way to check qs1.mistake.length>0 without knowing the key name(qs1).
Below is my function:
function SelectiMstake(value) {
alert(value);
var value2 = jQuery.parseJSON(value);
var NewHtml="";
if(value2.mistake.length>0) {
alert("mistake found");
//for(var mistakei = 0; mistakei < value2.mistake.length; mistakei++) {
// NewHtml+= "<input type='check' value='"+ value2.mistake[mistakei] +"'>"+ value2.mistake[mistakei] +"<br>";
// }
//$("#DisplayMistakes").html(NewHtml);
} else {
alert("No mistakes found in the following Question");
}
}
if there is no way I want to stick with my question part when I get JSON string then I want to remove {"qs1": from the start of the string and } from the last. Don't use a character to remove from the start otherwise {"qs12": this will give the wrong result.

Use Object.values(), and just select the first element, or loop through the values (Which is now an array), if you want to check each qs*:
var json = '{"qs1":{"mistake":[{"id":1,"name":"Subject-Verb Agreement Errors."},{"id":1,"name":"Sentence Fragments."},{"id":1,"name":"Missing Comma After Introductory Element."}]}}';
var parsed = JSON.parse(json);
var vals = Object.values(parsed);
console.log(vals[0]);
console.log(vals[0].mistake.length); // 3

How can I remove data by index array which is stored in local storage?

If I console.log(localStorage.getItem("cartCache")), the result like this :
{"dataCache":[{"id":20,"quantity":1,"total":100000,"request_date":"27-08-2017 20:31:00"},{"id":53,"quantity":1,"total":200000,"request_date":"27-08-2017 20:38:00"}],"expired":"2017-08-28T03:55:21.521Z"}
I want to remove the data in the cache by index array
For example, When I remove index array = 0, the result to be like this :
{"dataCache":[{"id":53,"quantity":1,"total":200000,"request_date":"27-08-2017 20:38:00"}]}
Another example, When I remove index array = 1, the result to be like this :
{"dataCache":[{"id":20,"quantity":1,"total":100000,"request_date":"27-08-2017 20:31:00"}]}
How can I do it?
I try like this :
var deleteIndex = 1;
var retrievedObj = localStorage.getItem("cartCache")
delete retrievedObj['dataCache'][deleteIndex];
It seems that is not the right way

localStorage.getItem("cartCache") returns you two objects - dataCache and expired. If you want to remove the element n of dataCache, remove it by
localStorage.getItem("cartCache").dataCache.splice(n,1);
To fit it in your code:
var deleteIndex = 1;
var retrievedObj = localStorage.getItem("cartCache");
retrievedObj.dataCache.splice(deleteIndex,1);
Then console.log your localStorage again and you'll see the element removed.

You can use splice to remove an item from the array
// Clearing all localStorage value. No need to use below line in your code
localStorage.clear();
// to be stored object
var x = {
"dataCache": [{
"id": 20,
"quantity": 1,
"total": 100000,
"request_date": "27-08-2017 20:31:00"
}, {
"id": 53,
"quantity": 1,
"total": 200000,
"request_date": "27-08-2017 20:38:00"
}],
"expired": "2017-08-28T03:55:21.521Z"
}
// Initially storing it in local storage using JSON.stringify
localStorage.setItem('storeData', JSON.stringify(x));
// Once stored retrieving the value using JSON.parse
var getItem = JSON.parse(localStorage.getItem('storeData'));
// setting the dataCache with new array. The new array will be created as splice is used. splice is used to remove an item from array,
//0 is the index of the array, while second parameter 1 is to represent how many item to be removed starting from 0 ndex
getItem.dataCache = getItem.dataCache.splice(0, 1);
console.log(getItem); // the modified object
// after operation setting it to local storage
localStorage.setItem('storeData', JSON.stringify(getItem))
DEMO

Keyword "delete" deletes deleteIndex only in retrieveObj it doesn't update your localStorage value. In order to update localStorage use:
var deleteIndex = 1;
var retrievedObj = localStorage.getItem("cartCache")
delete retrievedObj['dataCache'][deleteIndex];
localStorage.setItem("cartCache", retrieveObj)

Is there a way to iterate and display the list of key value pairs of json using Handlebar.js

As Iam new to javascript, I found handleBar.js can be used to template with dynamic data.
I worked on a sample which worked fine and the json structure was simple and straight forward.
(function()
{
var wtsource = $("#some-template").html();
var wtTemplate = Handlebars.compile(wtsource);
var data = { users: [
{url: "index.html", name: "Home" },
{url: "aboutus.html", name: "About Us"},
{url: "contact.html", name: "Contact"}
]};
Handlebars.registerHelper('iter', function(context, options) {
var fn = options.fn, inverse = options.inverse;
var ret = "";
if(context && context.length > 0) {
for(var i=0, j=context.length; i<j; i++) {
ret = ret + fn($.extend({}, context[i], { i: i, iPlus1: i + 1 }));
}
} else {
ret = inverse(this);
}
return ret;
});
var temp=wtTemplate(data);
$("#content").html(temp);
})();
<script id="some-template" type="text/x-handlebars-template">
{{#iter users}}
<li>
{{name}}
</li>
{{/iter}}
</script>
How to iterate a json with the below structure ? Please do suggest the possible way for iterating and creating the template for the below json structure
var newData = { "NEARBY_LIST": {
"100": {
"RestaurantID": 100,
"ParentRestaurantID": 0,
"RestaurantName": "Chennai Tiffin",
"listTime": [{
"startTime": "10:00",
"closeTime": "23:30"
} ]
},
"101": {
"RestaurantID": 101,
"ParentRestaurantID": 0,
"RestaurantName": "Biriyani Factory",
"listTime": [{
"startTime": "11:00",
"closeTime": "22:00"
}]
}
}
};

Accessing the properties of an object has nothing to do with Handlebars. If you dealing with JSON and you wish to access it in general bracket or dot notation, you must first parse the JSON into a JavaScript object using the JSON.parse() function.
After this is done, you may access the properties as follows.
var property = newData['NEARBY_LIST']['100'].RestaurantName; // "Chennai Tiffin"
Here is a fiddle to illustrate.
http://jsfiddle.net/qzm0cygu/2/

I'm not entirely sure what you mean, but if your question is how you can use/read the data in newData, try this:
newData = JSON.parse(newData); //parses the JSON into a JavaScript object
Then access the object like so:
newData.NEARBY_LIST //the object containing the array
newData.NEARBY_LIST[0] //the first item (key "100")
newData.NEARBY_LIST[1] //the second item (key "101")
newData.NEARBY_LIST[0][0] //the first field of the first item (key "RestaurantID", value "100")
newData.NEARBY_LIST[0][2] //the third field of the first item (key "RestaurantName", value "Chennai Tiffin")
newData.NEARBY_LIST[0][3][0] //the first field of the fourth field of the first item (key "startTime", value "11:00")
I hope this was what you were looking for.
EDIT: as Siddharth points out, the above structure does assume you have arrays. If you are not using arrays you can access the properties by using their names as if they're in an associative array (e.g. newData["NEARBY_LIST"]["100"]. The reason I say "properties" and "as if" is because technically JavaScript doesn't support associative arrays. Because they are technically properties you may also access them like newData.NEARBY_LIST (but I don't recommend that in this case as a property name may not start with a number, so you would have to use a mix of the different notations).
On that note, I would recommend using arrays because it makes so many things easier (length checks, for example), and there are practically no downsides.
EDIT2: also, I strongly recommend using the same camelcasing conventions throughout your code. The way you currently have it (with half your properties/variables starting with capitals (e.g. "RestaurantName", "RestaurantID") and the other half being in lowerCamelCase (e.g. "listTime", "startTime")) is just asking for people (you or colleagues) to make mistakes.

Adding a new array element to a JSON object

I have a JSON format object I read from a JSON file that I have in a variable called teamJSON, that looks like this:
{"theTeam":[{"teamId":"1","status":"pending"},{"teamId":"2","status":"member"},{"teamId":"3","status":"member"}]}
I want to add a new item to the array, such as
{"teamId":"4","status":"pending"}
to end up with
{"theTeam":[{"teamId":"1","status":"pending"},{"teamId":"2","status":"member"},{"teamId":"3","status":"member"},{"teamId":"4","status":"pending"}]}
before writing back to the file. What is a good way to add to the new element? I got close but all the double quotes were escaped. I have looked for a good answer on SO but none quite cover this case. Any help is appreciated.

JSON is just a notation; to make the change you want parse it so you can apply the changes to a native JavaScript Object, then stringify back to JSON
var jsonStr = '{"theTeam":[{"teamId":"1","status":"pending"},{"teamId":"2","status":"member"},{"teamId":"3","status":"member"}]}';
var obj = JSON.parse(jsonStr);
obj['theTeam'].push({"teamId":"4","status":"pending"});
jsonStr = JSON.stringify(obj);
// "{"theTeam":[{"teamId":"1","status":"pending"},{"teamId":"2","status":"member"},{"teamId":"3","status":"member"},{"teamId":"4","status":"pending"}]}"

var Str_txt = '{"theTeam":[{"teamId":"1","status":"pending"},{"teamId":"2","status":"member"},{"teamId":"3","status":"member"}]}';
If you want to add at last position then use this:
var parse_obj = JSON.parse(Str_txt);
parse_obj['theTeam'].push({"teamId":"4","status":"pending"});
Str_txt = JSON.stringify(parse_obj);
Output //"{"theTeam":[{"teamId":"1","status":"pending"},{"teamId":"2","status":"member"},{"teamId":"3","status":"member"},{"teamId":"4","status":"pending"}]}"
If you want to add at first position then use the following code:
var parse_obj = JSON.parse(Str_txt);
parse_obj['theTeam'].unshift({"teamId":"4","status":"pending"});
Str_txt = JSON.stringify(parse_obj);
Output //"{"theTeam":[{"teamId":"4","status":"pending"},{"teamId":"1","status":"pending"},{"teamId":"2","status":"member"},{"teamId":"3","status":"member"}]}"
Anyone who wants to add at a certain position of an array try this:
parse_obj['theTeam'].splice(2, 0, {"teamId":"4","status":"pending"});
Output //"{"theTeam":[{"teamId":"1","status":"pending"},{"teamId":"2","status":"member"},{"teamId":"4","status":"pending"},{"teamId":"3","status":"member"}]}"
Above code block adds an element after the second element.

First we need to parse the JSON object and then we can add an item.
var str = '{"theTeam":[{"teamId":"1","status":"pending"},
{"teamId":"2","status":"member"},{"teamId":"3","status":"member"}]}';
var obj = JSON.parse(str);
obj['theTeam'].push({"teamId":"4","status":"pending"});
str = JSON.stringify(obj);
Finally we JSON.stringify the obj back to JSON

In my case, my JSON object didn't have any existing Array in it, so I had to create array element first and then had to push the element.
elementToPush = [1, 2, 3]
if (!obj.arr) this.$set(obj, "arr", [])
obj.arr.push(elementToPush)
(This answer may not be relevant to this particular question, but may help
someone else)

Use spread operator
array1 = [
{
"column": "Level",
"valueOperator": "=",
"value": "Organization"
}
];
array2 = [
{
"column": "Level",
"valueOperator": "=",
"value": "Division"
}
];
array3 = [
{
"column": "Level",
"operator": "=",
"value": "Country"
}
];
console.log(array1.push(...array2,...array3));

For example here is a element like button for adding item to basket and appropriate attributes for saving in localStorage.
'<i class="fa fa-shopping-cart"></i>Add to cart'
var productArray=[];
$(document).on('click','[cartBtn]',function(e){
e.preventDefault();
$(this).html('<i class="fa fa-check"></i>Added to cart');
console.log('Item added ');
var productJSON={"id":$(this).attr('pr_id'), "nameEn":$(this).attr('pr_name_en'), "price":$(this).attr('pr_price'), "image":$(this).attr('pr_image')};
if(localStorage.getObj('product')!==null){
productArray=localStorage.getObj('product');
productArray.push(productJSON);
localStorage.setObj('product', productArray);
}
else{
productArray.push(productJSON);
localStorage.setObj('product', productArray);
}
});
Storage.prototype.setObj = function(key, value) {
this.setItem(key, JSON.stringify(value));
}
Storage.prototype.getObj = function(key) {
var value = this.getItem(key);
return value && JSON.parse(value);
}
After adding JSON object to Array result is (in LocalStorage):
[{"id":"99","nameEn":"Product Name1","price":"767","image":"1462012597217.jpeg"},{"id":"93","nameEn":"Product Name2","price":"76","image":"1461449637106.jpeg"},{"id":"94","nameEn":"Product Name3","price":"87","image":"1461449679506.jpeg"}]
after this action you can easily send data to server as List in Java
Full code example is here
How do I store a simple cart using localStorage?

How to access elements inside nested objects in a Javascript loop using variable names?

I'm clueless. I have a JSON string like this which I need to check for a supplied "property" (postsome in the following example):
var index_file =
[{
"indexAB":[
{ "postsome": ["keyword_abc", "keyword_def"] },
{ "testsome": ["keyword_111", "keyword_222"] }
]
},{
"index_random": [
{ "postsome": ["keyword_abc"] }
]
}]
There my be any number of indices ("indexAB", "index_random") with n objects inside.
I need to "find" my property postsome but I cannot get it to work, because I'm struggling with the correct way of accessing the object.
So:
for (var i = 0, l = indices.length; i < l; i += 1) {
doc._id = "postsome",
index_name = "indexAB";
indices[i]["indexAB"]; // ok, returns object on correct iteration
indices[i][index_name]; // undefined
indices[i].indexAB[0][doc._id] // ok, returns undefined or keywords
indices[i][index_name][0][doc._id] // undefined
}
Question:
How can I access a nested object in loop using a variable name index_name?

This is not a direct answer to your question but I believe that it may actually help you more than giving you a complicated way to access values in your object.
If instead of this JSON object:
var index_file =
[{
"indexAB":[
{ "postsome": ["keyword_abc", "keyword_def"] },
{ "testsome": ["keyword_111", "keyword_222"] }
]
},{
"index_random": [
{ "postsome": ["keyword_abc"] }
]
}];
you would have this much simpler data structure:
var index_file =
{
"indexAB": {
"postsome": ["keyword_abc", "keyword_def"],
"testsome": ["keyword_111", "keyword_222"]
},
"index_random": {
"postsome": ["keyword_abc"]
}
};
then it would be much easier to access, using just:
var value = index_file.indexAB.postsome[0]; // no loops, no nothing
// value == "keyword_abc"
See: DEMO
I think that what you should change is your data model because currently it is something that is very far from the idea of JSON and it will always be very hard do access data in it.

A couple of issues
"indexAB" only exists on the first element in the array
you cannot have dots inside variable names.
I suggest you test whether indexAB is a property of the object before deferencing it further. See example below:
Fixed
var indices = index_file;
for (var i = 0, l = indices.length; i < l; i++) {
var doc_id = "postsome";
var index_name = "indexAB";
indices[i]["indexAB"]; // ok, returns object on correct iteration
indices[i][index_name]; // undefined
if ("indexAB" in indices[i]) {
indices[i].indexAB[0][doc_id] // ok, returns undefined or keywords
indices[i][index_name][0][doc_id] // undefined
}
}

index_name is undefined because the line prior to that raises an error
doc._id = "postname" // this causes an error
Just use a simple string
doc = "postname"