fix: esm imports need js extension

[vasco-santos]

Because nodejs requires file extensions for relative imports, the current esm build fails to use in Node.js

As an example, importing packToBlob:

Error [ERR_UNSUPPORTED_DIR_IMPORT]: Directory import '/Users/vsantos/work/pl/gh/protocol/nft.storage/packages/client/examples/node.js/node_modules/ipfs-car/dist/esm/pack/' is not supported resolving ES modules imported from /Users/vsantos/work/pl/gh/protocol/nft.storage/packages/client/examples/node.js/node_modules/ipfs-car/dist/esm/pack/blob.js

This PR uses ttsc to rely on a custom transformer, which during the build adds the .js extension to relative imports. Note that index.js is not inferred and index needed to be added

Related:

• A compiler option to enforce file extensions. microsoft/TypeScript#42813
• Provide a way to add the '.js' file extension to the end of module specifiers microsoft/TypeScript#16577
• Proposal: make .js extension default for es6 imports nodejs/modules#444

[vasco-santos]

This seems to fix the problem (tested in nft.storage client Node.js example)

[alanshaw]

I think by spec you need the extension - why not just add it, instead of adding a plugin?

Incase you didn't know: you can import with .js in typescript and it'll do the right thing.

[vasco-santos]

I think by spec you need the extension - why not just add it, instead of adding a plugin?

Incase you didn't know: you can import with .js in typescript and it'll do the right thing.

Yes, it compiles fine and the resulting build works. But, when using ts-node it fails as it does not find file.js.

As we also use ts-node for the tests, it will fail. I could change the test setup, but I am not really a fan of just using the .js extension in the code imports to solve something that is related to the build.

[alanshaw]

Ahh ok gotcha. Plugin it is then!