JS_OOP_example1.js

// Example 1
const obj = {
  color: "blue",
  amount: 100,
};

// Check the type of the object literal 'obj'
console.log(typeof obj); // 'object'

// Verify that 'obj' has the properties we expect it to have
console.log(obj.hasOwnProperty('color')); // true
console.log(obj.hasOwnProperty('amount')); // true
console.log(obj.hasOwnProperty('randomProperty')); // false
console.log(obj.hasOwnProperty('hasOwnProperty')); // false

// Verify that 'obj.__proto__ === Object.getPrototypeOf(obj)'
// which are both equal to 'Object.prototype' for an object literal
// defined using the curly braces and assigning it to a variable.
console.log(Object.getPrototypeOf(obj) === Object.prototype); // true
console.log(obj.__proto__ === Object.prototype); // true

// Confirm that Object.prototype does indeed have the 'hasOwnProperty'
// method defined on it
console.log(Object.prototype.hasOwnProperty('hasOwnProperty'); // true

// Verify that the constructor of 'obj' is the 'Object' constructor function
// and check the type of the 'Object' constructor function which is an object
// of type 'function'
console.log(obj.constructor === Object); // true
console.log(typeof Object); // 'function'

// Similarly, the 'constructor' property of 'obj' is actually inherited from
// its prototype, Object.prototype
console.log(obj.hasOwnProperty('constructor')); // false
console.log(Object.prototype.hasOwnProperty('constructor')); // true

// Finally, check there is no 'prototype' property on 'obj'
// as only function objects have property 'prototype'
console.log(obj.prototype); // undefined