Add memoization to resources

[Olian04]

const A = createAtom({
  default: 42,
})

const C = createResource({
  get: async () => {
    return await fetch(`/${A.get()}`);
  }
);

await C.get(); // network request
await C.get(); // cached

A.set(3);
await C.get(); // network request
await C.get(); // cached

A.set(42);
await C.get(); // cached

A.invalidate();
await C.get(); // network request
await C.get(); // cached

Memoization will stringify and hash all dependencies, it will then store the return value of the resource/selector to be reused at a later time if the same dependency hash is encountered again.

Resources are memoized selectors optimized for cacheable, IO bound, or computationally heavy operations. Such as network requests, reading from a file, or calculating a complex calculation.

Ex:

const fileName = createAtom({
  default: 'cat.png',
})

const file = createResource({
  get: async ({ get }) => {
    return fetch(`/${fileName.get()}`)
  }
})

const fileEdges = createResource({
  get: async ({ get }) => {
    return getEdges(await file.get()) 
  }
})

createEffect(async () => {
  console.log(await fileEdges.get())
})

[Olian04]

Closed in favor of #28