Btukfyl

With ECMAScript 2015 you can do it directly in object declaration using bracket notation:

var obj = {

  [key]: value

}

Where key can be any sort of expression (e.g. a variable) returning a value:

var obj = {

  ['hello']: 'World',

  [x + 2]: 42,

  [someObject.getId()]: someVar

}

You can even make List of objects like this

var feeTypeList = ;

$('#feeTypeTable > tbody > tr').each(function (i, el) {

    var feeType = {};



    var $ID = $(this).find("input[id^=txtFeeType]").attr('id');



    feeType["feeTypeID"] = $('#ddlTerm').val();

    feeType["feeTypeName"] = $('#ddlProgram').val();

    feeType["feeTypeDescription"] = $('#ddlBatch').val();



    feeTypeList.push(feeType);

});

First we need to define key as variable and then we need to assign as key as object., for example

var data = {key:'dynamic_key',value:'dynamic_value'}

var key = data.key;

var obj = { [key]: data.value}

console.log(obj)

With lodash, you can create new object like this _.set:

obj = _.set({}, key, val);

Or you can set to existing object like this:

var existingObj = { a: 1 };

_.set(existingObj, 'a', 5); // existingObj will be: { a: 5 }

You should take care if you want to use dot (".") in your path, because lodash can set hierarchy, for example:

_.set({}, "a.b.c", "d"); // { "a": { "b": { "c": "d" } } }

There are two different notations to access object properties

• 
  Dot notation: myObj.prop1
  


• 
  Bracket notation: myObj["prop1"]
  

Dot notation is fast and easy but you must use the actual property name explicitly. No substitution, variables, etc.

Bracket notation is open ended. It uses a string but you can produce the string using any legal js code. You may specify the string as literal (though in this case dot notation would read easier) or use a variable or calculate in some way.

So, these all set the myObj property named prop1 to the value Hello:

// quick easy-on-the-eye dot notation

myObj.prop1 = "Hello";



// brackets+literal

myObj["prop1"] = "Hello";



// using a variable

var x = "prop1"; 

myObj[x] = "Hello";                     



// calculate the accessor string in some weird way

var numList = [0,1,2];

myObj[ "prop" + numList[1] ] = "Hello";     

Pitfalls:

myObj.[xxxx] = "Hello";      // wrong: mixed notations, syntax fail

myObj[prop1] = "Hello";      // wrong: this expects a variable called prop1

tl;dnr: If you want to compute or reference the key you must use bracket notation. If you are using the key explicitly, then use dot notation for simple clear code.

Note: there are some other good and correct answers but I personally found them a bit brief coming from a low familiarity with JS on-the-fly quirkiness. This might be useful to some people.

With the advent of ES2015 Object.assign and computed property names the OP's code boils down to:

var obj = Object.assign.apply({}, $(itemsFromDom).map((i, el) => ({[el.id]: el.value})));

objectname.newProperty = value;

If you want to add fields to an object dynamically, simplest way to do it is as follows:

 var params= [

{key: "k1", value=1},

{key: "k2", value=2},

{key: "k3", value=3}];



for(i=0; i< params.len; i++) {

  data[params[i].key] = params[i].value

}

This will create data object which has following fields:

{k1:1, k2:2, k3:3}

Based on the wOxxOm's answer, this is an example of use:

const data = [

    {"id": "z1", "val":10},

    {"id": "z2", "val":20},

    {"id": "z3", "val":30}

];

    

const obj = Object.assign.apply({}, data.map((el, i) => ({[el.id]: el.val})));



console.log(obj);

const data = [{

    name: 'BMW',

    value: '25641'

  }, {

    name: 'Apple',

    value: '45876'

  },

  {

    name: 'Benz',

    value: '65784'

  },

  {

    name: 'Toyota',

    value: '254'

  }

]



const obj = {

  carsList: [{

    name: 'Ford',

    value: '47563'

  }, {

    name: 'Toyota',

    value: '254'

  }],

  pastriesList: ,

  fruitsList: [{

    name: 'Apple',

    value: '45876'

  }, {

    name: 'Pineapple',

    value: '84523'

  }]

}



let keys = Object.keys(obj);



result = {};



for(key of keys){

    let a =  [...data,...obj[key]];

    result[key] = a;



}