Expose get and has methods

[epayet]

This has been mentioned in a few issues (#45, #33, #51).

The goal is to expose get and has methods so that we easily have read access to the cache, depending on the arguments.
Hopefully, the tests will demonstrate really well how this works.

I tried to match your coding style, I am happy to take any feedback.
This would be really useful for my use case described here: #33 (comment)

I know you're planning to do a major refactor soon, but in the meantime, I think that exposing those 2 new methods are costless and will be really useful to some people, me included :)

Many thanks.

[medikoo]

Thanks @epayet, at first glance looks good. I'm keen to take it but would prefer to give it a more careful look. If not today, I'll take care of this on Monday.

[epayet]

Sure @medikoo thanks for the quick response 👍

[medikoo]

Additionally there are two lint issues, you can see them by running npm run lint in a project.

Thank you!

[medikoo]

Let's exit early (before conf.has(..)) with false if id resolved to null (It can happen, e.g. https://github.com/medikoo/memoizee/blob/master/normalizers/get-1.js#L10 )

[epayet]

What you say is true, id can be null. But conf.has(null) always returns false. (hasOwnProperty.call(cache, null) will return false as expected.

I'm not sure we need an extra null check here

[medikoo]

Theoretically we can have 'null' cache id (e.g. with primitive serialization for one argument taking function, the null argument will resolve to 'null' cache id).
And in such case hasOwnProperty.call(cache, null) will result with true, as second argument is in all cases coerced by engine to string:

cache = { 'null': true };
Object.prototype.hasOwnProperty.call(cache, null); // true

[medikoo]

Let's ensure that extGet and extHas have ensured right lenght, it can be done through defineLength as here -> https://github.com/epayet/memoizee/blob/16601d1d0762d34a844c9916cbe791b34c936aca/lib/configure-map.js#L123

[epayet]

Done 👍

[medikoo]

Let's expose get as _get (so not as official Public API method). Thing is, that it doesn't work well with async mode, as it will return direct result of asynchronous function, and not asynchronously resolved value, as some may expect.
With v1 (hopefully today I'll post new API proposal) it'll be addressed properly

[epayet]

I did the renaming for both _has and _get. I did not think of the async mode and this is very important.
As you said I would expect to get the actual value, and not the result of an async function (like a Promise).
I started to write a test for what I would expect, but it is obviously failing because I get a promise back instead of the actual value of it, when resolved.
In the actual state of the library, this seems rather complex to implement now. It will be hopefully addressed on v1 :)

Just to show you what I would expect from it, here is the test case I wrote:

"has & get on Promise mode": function (a, d) {
    var fn = function (x) {
        return new Promise(function (res) {
            setTimeout(function () {
                res(x);
            }, 1);
        });
    }, mfn;
    mfn = memoize(fn, { promise: true });
    a(mfn.has('foo'), false);
    mfn('foo').then(function () {
        // At the moment, we get a solved promise instead of the value
        a(mfn.get('foo'), 'foo');
        a(mfn.has('foo'), true);
        d();
    });
    // Promise is not resolved, yet
    // At the moment, we get true, and an unresolved promise
    a(mfn.has('foo'), false);
    a(mfn.get('foo'), undefined);
},

[medikoo]

Yes, in v1, with get and has, you will always get resolved value, so final value in case of async and promise modes.
I also wrote an updated API proposal already -> #73 (although it doesn't explain that detail)

[epayet]

I like the API proposal, it would be nice to include this behaviour in :)

[epayet]

I gave it another go according to your requested changes. Can you have a look now and give your feedback?

I left a note on async on another comment, this is an interesting case that I hope will be solved in v1.
In the meantime, if you're happy with this code, it would still be very helpful.

Thanks :)

[medikoo]

@epayet looks great, just check my comment towards null handling :)

[epayet]

I added the null check for _has :)
And the build is green 👍

[medikoo]

Thank you, published with v0.4.4

[epayet]

Thanks I just checked, it works 👍