icache has no eviction mechanism for individual key/values

[matt-gadd]

Enhancement

Code

console.log(icache.getOrSet('foo', 'a'));
icache.set('foo', undefined);
console.log(icache.getOrSet('foo', 'b'));

Expected behavior:
logs:

a
b

Actual behavior:
logs:

a
undefined

This is due to there actually being a wrapper around all values in the cache, so getOrSet will never be called again, regardless of value.

We should probably define the undefined semantics here. Does setting a value to undefined mean it's empty and then getOrSet should call the setter here? Or should we have an explicit unset api? or should we have both?

[agubler]

@matt-gadd I'm thinking that using undefined consistently as the eviction semantics would be sufficient here as you should never need to store undefined explicitly in the cache given it returns undefined when a key is not available. What do you think?

[agubler]

After a little discussion, the other option is to add an API to deal with cache eviction. The benefit to this is that we don't have to deal with edge cases like icache.getOrSet('key', () => new Promise.resolve(undefined)); which could end up causing a render loop. Also it could aligns with the native map APIs that users should be familiar with and it would not be a breaking chance.