add property with value in js

JavaScript
let yourObject = {};

//Examples:
//Example 1
let yourKeyVariable = "yourKey";
yourObject[yourKeyVariable] = "yourValue";

//Example 2
yourObject["yourKey"] = "yourValue";

//Example 3
yourObject.yourKey = "yourValue";var myObject = {
    sProp: 'some string value',
    numProp: 2,
    bProp: false
};

Source

Also in JavaScript: