Create JSON object dynamically via JavaScript (Without concate strings)

Question

I have this JSON data:

{
    "employees": [
        {
            "firstName": "John",
            "lastName": "Doe"
        },
        {
            "firstName": "Anna",
            "lastName": "Smith"
        },
        {
            "firstName": "Peter",
            "lastName": "Jones"
        }
    ]
}

Suppose I don't know how many columns and rows of employees I have, how do I create this object in JavaScript (Without concate strings)? Assume that I get each row in "onGeneratedRow" method, and I need to push each column (firstName, lastName) to the '{}' brackets.

var viewData = { 
    employees : [] 
};

var rowNum = -1; 

function onGeneratedRow(columnsResult)
{
    rowNum = rowNum + 1;
    viewData.employees.push({});    
    columnsResult.forEach(function(column) {                  
    var columnName = column.metadata.colName;
    viewData.employees[rowNum][columnName] = column.value;  });
}

This questions does not make sense to me at present, can you explain further, where is your data coming from and in what format. Are you just adding to existing data or creating all of it from scratch. Maybe you can create a jsfiddle to demonstrate what the problem you are having is.Is your question really just, how to access data within an array/ or javascript object? And lets be clear about the data, JSON or Javascript object: http://stackoverflow.com/questions/8294088/javascript-object-vs-json — Xotic750, May 12 '13 at 12:20
assume "columnName" is "firstName" and "column.value" is the value (for example: "John"). I just need to know how to push them dynamically into the brackets ('{}') — ohadinho, May 12 '13 at 12:24
@ohadinho it is unclear what is your input data strucuture (json) `columnsResult` — Kamil Kiełczewski, Apr 25 '19 at 10:24

Waqar Alamgir · Accepted Answer · 2013-05-12T12:28:10.283

195

This is what you need!

function onGeneratedRow(columnsResult)
{
    var jsonData = {};
    columnsResult.forEach(function(column) 
    {
        var columnName = column.metadata.colName;
        jsonData[columnName] = column.value;
    });
    viewData.employees.push(jsonData);
 }

edited May 12 '13 at 12:28

answered May 12 '13 at 12:15

Waqar Alamgir

9,828
4
30
36

How did you know that the OP does not need to count the rows with ´rowNum´? – Xotic750 May 12 '13 at 12:45
1

push does not need row number – Waqar Alamgir May 12 '13 at 13:06
because json generation does not need count, more you can always use .length to get rows. – Waqar Alamgir May 12 '13 at 13:19
5

I never said that JSON generation does. It was more the case that you state "This is what you need!", but I wanted to know how you knew that count was not needed by the OP, or did you just assume? Your answer does not generate JSON btw. – Xotic750 May 12 '13 at 13:34
1

@WaqarAlamgir - that's exactly what I needed at this moment. Cheers! – bob.mazzo Jun 25 '14 at 17:33
what is columnsResult? – Teekam Sep 07 '16 at 10:05

Xotic750 · Answer 2 · 2016-12-15T04:13:37.860

Perhaps this information will help you.

var sitePersonel = {};
var employees = []
sitePersonel.employees = employees;
console.log(sitePersonel);

var firstName = "John";
var lastName = "Smith";
var employee = {
  "firstName": firstName,
  "lastName": lastName
}
sitePersonel.employees.push(employee);
console.log(sitePersonel);

var manager = "Jane Doe";
sitePersonel.employees[0].manager = manager;
console.log(sitePersonel);

console.log(JSON.stringify(sitePersonel));

score 20 · Answer 3 · edited Dec 17 '17 at 11:31

This topic, especially the answer of Xotic750 was very helpful to me. I wanted to generate a json variable to pass it to a php script using ajax. My values were stored into two arrays, and i wanted them in json format. This is a generic example:

valArray1 = [121, 324, 42, 31];
valArray2 = [232, 131, 443];
myJson = {objArray1: {}, objArray2: {}};
for (var k = 1; k < valArray1.length; k++) {
    var objName = 'obj' + k;
    var objValue = valArray1[k];
    myJson.objArray1[objName] = objValue;
}
for (var k = 1; k < valArray2.length; k++) {
    var objName = 'obj' + k;
    var objValue = valArray2[k];
    myJson.objArray2[objName] = objValue;
}
console.log(JSON.stringify(myJson));

The result in the console Log should be something like this:

{
   "objArray1": {
        "obj1": 121,
        "obj2": 324,
        "obj3": 42,
        "obj4": 31
   },
   "objArray2": {
        "obj1": 232,
        "obj2": 131,
        "obj3": 443
  }
}

Can I stress the usefulness in properly spacing the code you submit here? It's much harder to read without spacing. — Kevin Lewis, Dec 26 '15 at 10:35

score 1 · Answer 4 · edited Feb 15 '19 at 13:45

1

JavaScript

var myObj = {
   id: "c001",
   name: "Hello Test"
}

Result(JSON)

{
   "id": "c001",
   "name": "Hello Test"
}

edited Feb 15 '19 at 13:45

Tirolel

928
3
17
43

answered Feb 04 '19 at 06:25

Ishan Lakshitha

365
3
6

Create JSON object dynamically via JavaScript (Without concate strings)

4 Answers4

Linked