Priority-based merging

[NightProgramming]

The current approach is based on direction:

const x = { key1: null };
const y = { key1: new Date() };
const z = { key1: undefined };

const merged = deepmerge(x, y, z);
console.log(merged.key1); // Gives undefined because the right most value 'wins'.

Maybe there could be an option to go by priority instead of direction:

const w = { key1: null };
const x = { key1: new Date() };
const y = { key1: undefined };
const z = { key1: [] };

const merged = deepmergeWithOptions({priorityMerging: true}, w, x, y, z);

Here is the priority used by object-merge-advanced. So according to that the winner would be the date object (meaning merged.key1 contains the date). But I guess even custom priorities would be thinkable, defined by an array of symbols or strings describing the priority of different kinds of values e.g. ["emptyArray", "null"] would prioritize empty arrays higher than null values.

Yet again this can already be done via custom merging, but maybe some support for this would be nice.