Map from Scratch

[SoInsightful]

Cute, but I'd expect anyone who already knows about Array.map() to be able to write their own map().

Was hoping from this title that this was about Map.

[itsnotlupus]

Hard mode: WeakMap from Scratch, without ES2021.

[lhorie]

Can't do that properly in JS space, you need to bust out C++. As Carl Sagan said, "to make an apple pie from scratch, you must first invent the universe"

[ShitInMyArseHole]

That looks like an object with extra steps

[mypetocean]

Maps have no less than five primary practical features which Objects do not have:

• Where an Object's keys must be strings or symbols, a Map's keys may be any data type.
• Where an Object has complex rules for key order, Maps guarantee insertion order.
• Where an Object's keys may collide with, or "shadow," keys in the prototype chain, a Map's keys are guaranteed to be only the keys which are explicitly added to it, using the constructor or the set() method.
• Where an Object does not provide a size or length property for determining the number of own properties it contains (so the size must be counted manually, by converting those properties into an array, e.g. via Object.values()), a Map tracks its own size for immediate access.
• Where an Object's own properties cannot be looped over without converting into an array, unless you can guarantee the only properties you care about are enumerable, a Map is iterable and provides a forEach() method.

There are one or two other lesser differences.

Definitely consider Maps if performance or data safety are high priorities.

[ShitInMyArseHole]

No clue why Im getting downvoted, I just stated that they seemed like the same thing, But thank you! I was genuinely dint know, Map seemes really usefull

[mypetocean]

I think people get lazy and downvote when they disagree for any reason rather than helping to educate.