Assign some random thing to the instance method

object_defineProperty_vuejs.js

import moment from 'moment';
Object.defineProperty(Vue.prototype, '$moment', { value: moment });
/*it gives us a distinct advantage: properties created with a descriptor are read-only by default.
Instead, our read-only instance method protects our library, and if you attempt to overwrite it you will get "TypeError: Cannot assign to read only property".*/

/*
We would normally set an object property like this:
Vue.prototype.$moment = moment; */