Options hash about nano-memoize HOT 6 CLOSED

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For single object arguments, when not providing a serializer, the lib defaults to using a weakmap.
Weakmaps compare keys by reference.

You're passing a different object reference in the calls you make to your memoized function.
So the internal weakmap does not have an entry for the object in the second call.

For single argument function such as yours, either:

1. Call your function as follows:

const obj = { foo: 'foo', bar: fib };
mfn(obj); // miss
mfn(obj); // hit

2. Provide a serializer function.

If a serializer function is provided, and no equals function is provided, the lib will use the serializer function's returned value as a key in the cache (which is a plain object).

So the serializer must return values that can be keys in plain javascript objects - strings or numbers.

The most common is stringifying objects.

obj => JSON.stringify(obj)

... or other string representations that suit you.

If your objects have unique identifier/s and your function only cares about the identity of the objects, I'd return just the identifier/s.

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Make sense, thanks for the info!

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@igalklebanov thanks for jumping in with a response

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@richardscarrott JSON.stringify is slow. Suggest you try to avoid it.

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@anywhichway yeah I've found it to be slow. Ultimately I'd like fn({ a, b, c }) and fn(a, b, c) to be treated in the same way; i.e. I'd like a, b and c to be compared by identity.

const fib = new Fib(); // assume Fib cannot be serialized w/ `JSON.stringify` or `toString`

// This works by default
mfn('foo', 'bar', fib) // miss
mfn('foo', 'bar', fib) // hit
mfn('foo', 'bar', new Fib()) // miss

// But this is obv a miss every time
mfn2({ a: 'foo', b: 'bar', c: fib }) // miss
mfn2({ a: 'foo', b: 'bar', c: fib }) // hit
mfn2({ a: 'foo', b: 'bar', c: new Fib() }) // miss

How does nano-memoize serialize fn(a, b, c) under the hood?

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