create object key value js code example

Example 1: javascript create object key from variable

//For ES6 and Babel
{
    [yourKeyVariable]: "yourValue",
}

// ES5 Alternative
// Create the object first, then use [] to set your variable as a key
var yourObject = {};

yourObject[yourKeyVariable] = "yourValue";

Example 2: how to add field to object in js

// original object { key1: "a", key2: "b"}
var obj = {
    key1: "a",
    key2: "b"
};

// adding new filed - you can use 2 ways
obj.key3 = "c"; // static
// or
obj["key3"] = "c"; // dynamic - 'key3' can be a variable
console.log(obj) // {key1: "a", key2: "b", key3: "c" }

Example 3: javascript add to object

var element = {}, cart = [];
element.id = id;
element.quantity = quantity;
cart.push(element);

// Array of Objects in form {element: {id: 10, quantity: 10} }
var element = {}, cart = [];
element.id = id;
element.quantity = quantity;
cart.push({element: element});

Example 4: js create object with keys

var users = [{userId: "1", name: 'harald'}, {userId: "2", name: 'jamie'}];    
var obj = {};
users.forEach(user => {
  obj = {
    ...obj,
    [user.userId]: user,
  }
})
console.log(obj)
// {
//   1: {userId: "1", name: "harald"}
//   2: {userId: "2", name: "jamie"}
// }