µmap 🗺

 

The smallest, yet handy, Map and WeakMap utility ever.

``js
import umap from 'umap';
// const umap = require('umap');

const map = umap(new Map);
console.assert(
(map.get(1) || map.set(1, Math.random())) ===
(map.get(1) || map.set(1, Math.random())),
'a very common pattern I have with Map instances'
);

const weakMap = umap(new WeakMap);
console.assert(
(weakMap.get(map) || weakMap.set(map, Math.random())) ===
(weakMap.get(map) || weakMap.set(map, Math.random())),
'which I use even more with WeakMap instances'
);
`

$3

I am super tired of creating workarounds for the fact map.set(key, value) doesn't return value but the map itself, and so does the _WeakMap_.

This module will help, at least me, dropping all one-off helpers, here and there, to always do the same thing:

`js
// before 😢
const cache = new WeakMap;
const setThing = (key, value) => {
cache.set(key, value);
return value;
};
const thing = cache.get(key) || setThing(key, value);

// with umap 🎉
const cache = umap(new WeakMap);
const thing = cache.get(key) || cache.set(key, value);
``

$3

This module is meant to solve one pattern only, and it does exactly that, so that if you store _falsy_ values in _Maps_ or _WeakMaps_, it is not a concern of this module.