diffObjects.js

"use strict";

function diffObjects( a, b ) {
	var ak, diff = {};

	Object.entries( b ).forEach( ( [ k, val ] ) => {
		ak = a[ k ];
		if ( ak !== val ) {
			if ( !val || typeof val !== "object" ) {
				diff[ k ] = val;
			} else if ( Array.isArray( val ) ) {
				if ( !Array.isArray( ak ) || ak.toString() !== val.toString() ) {
					diff[ k ] = Array.from( val );
				}
			} else {
				diff[ k ] = diffObjects( ak || {}, val );
				if ( !Object.keys( diff[ k ] ).length ) {
					delete diff[ k ];
				}
			}
		}
	} );
	return diff;
}

Be careful, this algorithm consider Arrays like an atomic value, like String, Number, etc.
You must prevent at the maximum the use of Array to store Objects if you want to use this algorithm.