How to increment a value in a JavaScript object?

Question

var map = {};
map[key] = value;

How can I

• assign value 1 if key does not yet exist in the object
• increment the value by 1 if it

Answer 1

Creating an object:

    tagObject = {};
    tagObject['contentID'] = [];  // adding an entry to the above tagObject
    tagObject['contentTypes'] = []; // same explanation as above
    tagObject['html'] = [];

Now below is the occurrences entry which I am affffding to the above tag Object..

ES 2015 standards: function () {} is same as () => {}

          let found = Object.keys(tagObject).find(
                (element) => {
                    return element === matchWithYourValueHere;
                });

          tagObject['occurrences'] = found ? tagObject['occurrences'] + 1 : 1;

this will increase the count of a particular object key..