Auto-generate shield() calls using template literal types, #23

[louwers]

As discussed, a Draft MR for #23 👍

Action points:

• Getting the contents of types.ts for the test and inside the transformer in a clean way (i.e. without using __dirname). (See FIXME inside transform.ts and transformer.spec.ts).
• I realized that I didn't consider optional tuple elements, so they are currently broken. This is a problem for optional function arguments:

export function doSomething(arg: string, arg2?: string)

• Another case I realized is tuples which contain undefined or null. [string, null]. Right now this is unrepresentable with shield(). Not such a big problem because who would want this. But it should just fail to generate a shield() call at all if someone tries.

[brillout]

Performance shouldn't be a problem, but let's have an idea of how long the transpilation is delayed by the new transformer.

Worst case we only apply the transformer for prod building. Since the user's IDE already does the type checking job in dev. We can always make this an option.

[louwers]

@brillout W.r.t performance I generated this file: https://gist.github.com/louwers/392db2e700f9f597d8eecc24b7836c1f

Good news, transformer disabled:

real    0m0,881s
user    0m0,806s
sys     0m0,085s

Enabled:

real    0m2,883s
user    0m4,400s
sys     0m0,159s

Which is very good for such a complex types and so many functions. So I'd say we just keep it enabled for dev mode, but monitor real-world performance.

Bad news: I found that the diagnostics I use for extracting the value of template literal types gets cut off:

Encountered unrecognized emit message:  Type '"fun94"' is not assignable to type '"[
t.union(t.const(94), { geometries:t.array(t.union({ coordinates: t.array(t.array(t.array(
t.array(t.number)))), type: t.const('MultiPolygon') }, { coordinates: t.array(t.array(t.array(
t.number))), type: t.const('Polygon') }, { type: t.const('MultiLineString'), coordinates:
t.array(t.array(t.array(t.number))) }, { ...'.

so I have to find a better approach. The author of ts-morph is likely on it as well: dsherret/ts-morph#1266

[brillout]

I'd say we just keep it enabled for dev mode, but monitor real-world performance.

👍 We may want to have development experience that is as fast as possible development, so yea let's monitor on real world apps.

Bad news: I found that the diagnostics I use for extracting the value of template literal types gets cut off:

Seems like it would happen only rarely and, more importantly, deterministically though.

[brillout]

Btw. a potential solution for the problem of the emit info being truncated:

I can see that the threshold for truncating to be some const variable in TypeScript.

If that's the case then it's easy to change it to some big number 9999 in a post-install script. (I believe TypeScript ships as JavaScript and not binary; should be easy to patch TypeScript.)

We pin TypeScript and check if the patch still works when we use a newer TypeScript version.

[louwers]

Btw. a potential solution for the problem of the emit info being truncated:

I can see that the threshold for truncating to be some const variable in TypeScript.

If that's the case then it's easy to change it to some big number 9999 in a post-install script. (I believe TypeScript ships as JavaScript and not binary; should be easy to patch TypeScript.)

We pin TypeScript and check if the patch still works when we use a newer TypeScript version.

I'm using .getLiteralValue() in a way that seems to work consistently now!

[brillout]

function hello(name: 'some-t.string') {
}

I believe this would break?

[louwers]

Oops.

[brillout]

Let me know when the problem function hello(name: 'some-t.string') is solved. I'll then merge. FYI: I renamed variables to be consistent with the rest of Telefunc's source, and added an e2e test to examples/vite/.

[louwers]

Let me know when the problem function hello(name: 'some-t.string') is solved. I'll then merge. FYI: I renamed variables to be consistent with the rest of Telefunc's source, and added an e2e test to examples/vite/.

Awesome! 🎉 I'll let you know.

[louwers]

Made an additional fix to make sure single quotation marks are escaped.

[brillout]

Released in 0.1.20.