JSFiddle - React, Tailwind, and code Playground

JavaScript

myObject = { 
a1: 'dont-care',
a2: 'dont-care',
a3: 'dont-care',
a4: 'am i null?',
a5: 'am i null?',
a50: 'am i null?'
};

var result = Object.keys(myObject)
    .every(function(key) {
        switch (key) {
            case "a1": case "a2": case "a3":
                return true;
            default:
                return myObject[key] === null;
        }
    });

alert(result);