JSFiddle - React, Tailwind, and code Playground

JavaScript

var obj = {
    prop1: undefined,
    prop2: undefined
};

function defineGetter(obj, callback) {
    Object.keys(obj).forEach(function (key) {
        Object.defineProperty(obj, key, {
            get: callback.bind(obj, key)
        });
    });
}

defineGetter(obj, function (key) {
    if (key === "prop1") {
        return 0;
    } else if (key === "prop2") {
        return 1;
    }
});

console.log(obj.prop1);
console.log(obj.prop2);