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Get value from object/array [duplicate]

This question already has answers here:
JavaScript property access: dot notation vs. brackets?
(17 answers)
How can I access and process nested objects, arrays, or JSON?
(31 answers)
Closed 1 year ago.
I need to get the token only in a variable in JS.
{
"user": {
"id": "string",
"nickName": "string",
"score": 0,
"rank": 0
},
"token": "string"
}
This is my response saved in a variable but I only need to get the "String" value from the token

If you have stored this response in a variable E.g.:
let response = {
"user": {
"id": "string",
"nickName": "string",
"score": 0,
"rank": 0
},
"token": "string"
}
You can extract the value from the "token" property like this
let tokenFromObject = response.token
or
let tokenFromObject = response["token"]
or
let { token } = response

You should be able to take the variable you got this json in and do this:
let a = {"user":{},"token": "string"}; // this is what you got
console.log(a["token"]) // a["token"] will give you "string"

see undefined when try to parse json [duplicate]

This question already has answers here:
How can I access and process nested objects, arrays, or JSON?
(31 answers)
Closed 3 years ago.
I have tried to parse this JSON file. But I see undefined.
I need to receive only value, where the key equals level1.
[{
"id": 2,
"name": "Peter",
"products": [{
"title": "first",
"price": 100
},
{
"title": "second",
"price": 200,
"desciption": [{
"level1": "good",
"level2": "bad"
},
{
"level3": "super",
"level4": "hell"
}
]
}
],
"country": "USA"
}]
const fs = require('fs');
let file = fs.readFileSync("./file.json");
let parsed = JSON.parse(file);
console.log(parsed["name"])
console.log(parsed.name);
and I see in the conlose "undefined"

Your JSON data represents an array of objects. If after parsing you want the property "name" of the first element, it's:
console.log(parsed[0]["name"])
or
console.log(parsed[0].name);

Delete an object in Scope

This question might not even be related to angularjs and the solution could be plain old js or jquery. But that is what i what to find out.
I want to implement a delete functionality for a particular user and i am wondering if there is a easier way to do this in angularjs or should it be plain old JS?
i have a fairly complex object for eg (going up to 4 levels):
{
"Department": [
{
"Name": "Accounting",
"users": [
{
"id": "1",
"firstName": "John",
"lastName": "Doe",
"age": 23
},
{
"id": "2",
"firstName": "Mary",
"lastName": "Smith",
"age": 32
}
]
},
{
"Name": "Sales",
"users": [
{
"id": "3",
"firstName": "Sally",
"lastName": "Green",
"age": 27
},
{
"id": "4",
"firstName": "Jim",
"lastName": "Galley",
"age": 41
}
]
}
]
}
this is displayed in a ng-repeat where we should Department and username. If I want to delete a particular user i make an api call and on success of it, I want to delete that object. so i have a js method like this
function DeleteUser(user) {
$.each(ctrl.UserData, function(index, value) {
var filteredPeople = value.filter((item) => item.id !== user.id);
});
The question I have is, if i want to delete this object is there any easier way to delete from model since i have the object here or i have to do the classic jquery way of using like $.grep or filter to iterate through each object and match by id and then delete it?

Presumably, you're iterating over the departments (accounting, sales) in your template, and then over the users in that department.
So you could have, in your template:
<button ng-click="deleteUser(user, department)">...</button>
And the method could thus be as simple as
$scope.deleteUser = function(user, department) {
// delete user from backend, then
department.users.splice(departments.users.indexOf(user), 1);
}
If you really don't want to pass the department, then loop over the departments, and use the above if departments.users.indexOf(user) returns a value that is >= 0.

How to get specific array from JSON object with Javascript?

I am working with facebook JS SDK which returns user's information in JSON format. I know how to get the response like response.email which returns email address. But how to get an element from a nested array object? Example: user's education history may contain multiple arrays and each array will have an element such as "name" of "school". I want to get the element from the last array of an object.
This is a sample JSON I got:-
"education": [
{
"school": {
"id": "162285817180560",
"name": "Jhenaidah** School"
},
"type": "H**hool",
"year": {
"id": "14404**5610606",
"name": "2011"
},
"id": "855**14449421"
},
{
"concentration": [
{
"id": "15158**968",
"name": "Sof**ering"
},
{
"id": "20179020**7859",
"name": "Dig**ty"
}
],
"school": {
"id": "10827**27428",
"name": "Univer**g"
},
"type": "College",
"id": "9885**826013"
},
{
"concentration": [
{
"id": "108196**810",
"name": "Science"
}
],
"school": {
"id": "2772**996993",
"name": "some COLLEGE NAME I WANT TO GET"
},
"type": "College",
"year": {
"id": "1388*****",
"name": "2013"
},
"id": "8811215**16"
}]
Let's say I want to get "name": "some COLLEGE NAME I WANT TO GET" from the last array. How to do that with Javascript? I hope I could explain my problem. Thank you

Here is a JsFiddle Example
var json = '{}' // your data;
// convert to javascript object:
var obj = JSON.parse(json);
// get last item in array:
var last = obj.education[obj.education.length - 1].school.name;
// result: some COLLEGE NAME I WANT TO GET

If your json above was saved to an object called json, you could access the school name "some COLLEGE NAME I WANT TO GET" with the following:
json.education[2].school.name

If you know where that element is, then you can just select it as already mentioned by calling
var obj = FACEBOOK_ACTION;
obj.education[2].school.name
If you want to select specifically the last element, then use something like this:
obj.education[ obj.education.length - 1 ].scool.name

Try this,
if (myData.hasOwnProperty('merchant_id')) {
// do something here
}
where JSON myData is:
{
amount: "10.00",
email: "someone#example.com",
merchant_id: "123",
mobile_no: "9874563210",
order_id: "123456",
passkey: "1234"
}
This is a simple example for your understanding. In your scenario of nested objects, loop over your JSON data and use hasOwnProperty to check if key name exists.

How to use jquery to handle multiple json objects

I am developing a website with front-end and back-end separated. I used jquery to send request and get the result as a json object:
{
"item": [
],
"shop": [
],
"user": [
{
"user_id": "9",
"full_name": "Minh Duc",
"email": "nguyenminhduc1803#gmail.com",
"fb_link": "https:\/\/www.facebook.com\/SieuNhan183",
"user_name": "Duc",
"password": "37cd769165eef9ba6ac6b4a0fdb7ef36",
"level": "0",
"admin": "0",
"dob": "1996-03-18",
"location": "Ho Chi Minh",
"user_image_url": null
}
]
}
Now i am finding a way to get the data from the object user. How can i do it with javascript?

Complementing #arcs answer, remember that in Javascript you can access members of an object using dot notation (data.user[0].user_id) or square brackets notation. This way:
data['user'][0]['user_id']
this is useful because you can have a 'class' array and then do things like:
['item', 'shop', 'user'].forEach((array) => processArray(data[array][0]));
then you can filter only some classes or do more advanced stuff

When you have the data (in example it's in data) use the dot notation to get the node with the user.
The user is an array, so use [] to access a single element, e.g. [0]
var data = {
"item": [
],
"shop": [
],
"user": [
{
"user_id": "9",
"full_name": "Minh Duc",
"email": "nguyenminhduc1803#gmail.com",
"fb_link": "https:\/\/www.facebook.com\/SieuNhan183",
"user_name": "Duc",
"password": "37cd769165eef9ba6ac6b4a0fdb7ef36",
"level": "0",
"admin": "0",
"dob": "1996-03-18",
"location": "Ho Chi Minh",
"user_image_url": null
}
]
}
console.log( data.user[0].user_id )

I prefer use square brackets like this :
$jsonObject["user"][0]["user_id"]
but you can use the dot like this :
data.user[0].user_id
is the same thing.
If you want check if property exist you can do it :
if(typeof $jsonObject["user"] !== 'undefined'){
//do domethings as typeof $jsonObject["user"][0]["user_id"]
}
If you want get property dinamically you can do it :
const strId = "id";
const strName = "name";
//get user_id
let user_id = $jsonObject[user][0]["user_" + strId ];
//get user_name
let user_name = $jsonObject[user][0]["user_" + strName];
but there isn't very pretty.