[ethers-v5] Contract types not exported in generated index.ts

[tuler]

The index.ts only reexports the factory types, it does not export the contract types, the ones at <ContractName>.d.ts.
These types should also be exported.

[zemse]

I did try this in my PR but faced some typescript errors.

I had two ways of doing this:

1. Export both definations and factories from index.ts

Issue: Typescript doesn't complain at all. ts-node throws an error (in my project which consumes typechain and runs mocha tests with ts-node) while requiring these files:

/project-path/node_modules/ts-node/src/index.ts:586
          throw new TypeError(
                ^
TypeError: Unable to require file: build/typechain/ERC20.d.ts
This is usually the result of a faulty configuration or import. Make sure there is a `.js`, `.json` or other executable extension with loader attached before `ts-node` available.

2. An attempt to fix faulty export I tried exporting definitions from index.d.ts and factories from index.ts

Issue: Now typescript complains because it tries to look in index.ts and ignores index.d.ts for the contract types.

So I gave up for this one while submitting PR #250 thinking to look at later. @krzkaczor, anything we can do to do this or could this be a bug in ts-node? Since typescript doesn't error for the first case, I think this can be done someway.

Edit: I can recall that I tried the solution mentioned in TypeStrong/ts-node#797, but it doesn't solve the problem.

[tuler]

@zemse do you still have a branch with that try hanging around?
How did you try the re-export of option 1?

It should be:

export * from "./<ContractName>";

not

export * from "./<ContractName>.d.ts";

[zemse]

I was using export * from "./<ContractName>.d";. Pushed it here.

I tried with export * from "./<ContractName>";, it errors Error: Cannot find module './<ContractName>'

[zemse]

export * from "./<ContractName>";

Does this line in your index.ts file work in your project repo?

[tuler]

This change works for me.

-  .map((fileName) => [`export * from './${fileName}Factory'`, `export * from './${fileName}.d'`].join('\n'))
+  .map((fileName) => [`export * from './${fileName}Factory'`, `export * from './${fileName}'`].join('\n'))

But there is a catch. I know it only makes sense to export factories of contracts which are concrete, excluding abstracts and interfaces.

But it makes sense to export types of interfaces. In fact when you cast a contract in your test code you should usually cast to the interface, not the concrete implementation.

[zemse]

Hi, I looked into this, still getting error. I have created a minimal reproduction repo with typescript files.

https://github.com/zemse/types-import-problem

The typescript compiler doesn't give any error. But when you run the code with node js, it gives an error for the type file.

Can you have a look?

[tuler]

I see the problem. tsc does not use and does not copy the type definition file (.d.ts) to the destination folder.
So why don't you rename type.d.ts to type.ts, and let tsc generate the type.d.ts?

I mean:
https://github.com/zemse/TypeChain/blob/445ecfff8f141dfe22b3dcc66bbd4dd61e723496/packages/target-ethers-v5/src/index.ts#L99

-      path: join(this.outDirAbs, `${contract.name}.d.ts`),
+      path: join(this.outDirAbs, `${contract.name}.ts`),

[zemse]

That really needs to be a type definition file because it only has method signatures and doesn't have method implementations. You can see that by renaming a generated .d.ts file into .ts.

I think it could be something unexpected happening on the typescript side (since TS compiler doesn't error) so I've created a thread on Typescript repo microsoft/TypeScript#40517.

[tuler]

Even though it only defines types I think it should be a .ts not a .d.ts file.
Everything in a .d.ts file can be in a .ts file.
Let the compiler generate the type definition for you, like it is doing for the factories.

[zemse]

Everything in a .d.ts file can be in a .ts file.

There are methods in it without implementations which doesn't make sense in a .ts file.

I think we would need the following structure:

<ContractName>.js // exports actual js logic `ContractFactory`
<ContractName>.d.ts // exports type definations of `Contract` and `ContractFactory`.
...
...
index.js // exports js `ContractFactory` objects
index.d.ts // exports all type definations of `Contract` and `ContractFactory

I see this way it is possible. I can give a trial on this later this month. cc: @krzkaczor

[krzkaczor]

Can u help me to understand why it's needed at all? I just import directly from exact files. CC: @quezak :)

[tuler]

Imagine you want to create a reusable npm package with the code generated by TypeChain, instead of generating it on demand in every project you want to use it.

In that case you want a package.json main key and a typescript types key with everything you typically need in the usage of package, which includes the contract types, so you can just do import { MyContract } from "my_package";.

In the current state you have to do some trickery by copying the .d.ts files over to the tsc destination directory.

[quezak]

I agree that adding a barrel file index.d.ts would help in some cases. IMO we can do this -- it has little overhead on the generation process and is not a breaking change.

[krzkaczor]

Okay, I get it now. @zemse it would be cool if you could work on this.

[zemse]

Planning to work on it this weekend

I agree that adding a barrel file index.d.ts would help in some cases. IMO we can do this -- it has little overhead on the generation process and is not a breaking change.

I did not have luck with having index.d.ts in presence of index.ts. When I try to import, the module resolver gives preference to index.ts, and seems that the index.d.ts file ends up getting ignored.

I thinking to go ahead with this solution #278 (comment). And with this pattern, I think this would be a breaking change since there would be ERC20.js and ERC20.d.ts file (example). Those importing directly from index.ts won't face the problem, but to those who imported from ERC20Factory.ts since the file would be removed (replaced into ERC20.js). Please correct me if I'm wrong.