'use strict';

// Removes unwanted properties and adds undefined properties with default values
const defaultObject = (obj, defaultProperties) => {
	const defaultKeys = Object.keys(defaultProperties);
	// Remove unwanted keys
	Object.keys(obj).forEach(key => {
		if (!defaultKeys.includes(key))
			delete obj[key];
	});
	// Add missing keys
	defaultKeys.forEach(key =>
		obj[key] = typeof obj[key] === 'undefined' ? defaultProperties[key] : obj[key]
	);
	return obj;
};

// Example
console.log(defaultObject(
	{
		a: 'a',
		b: 'b',
	},
	{
		b: 'a',
		c: 'c'
	}
));

/*
	Changes first object to; and returns:
	{
		b: 'b',
		c: 'c'
	}
*/