Support typescript@4.5 .js import extension requirement

[vjpr]

ESM requires all relative imports to use an extension. TS requires insists on using .js inside .ts files which is left untouched in the output file.

See: https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-5.html

relative import paths need to use extensions

When a .ts file is compiled as an ES module, ECMAScript import/export syntax is left alone in the .js output

As a result, it will have to be rewritten to use the extension of the output of foo.ts - so bar.ts will instead have to import from ./foo.js.

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When trying to resolve #src/index.js from a TypeScript file, it should search for #src/index.ts. The extension needs to be stripped during search.

I use this for transpilation on-the-fly.

Would be nice to have a setting to accomplish this.

Workaround

I could just remove '.js' extensions before passing them to enhanced-resolve.

[alexander-akait]

We have options and plugins, you can do it using them, it should be done in ts-loader

[vjpr]

I am actually using it in an node --experimental-loader hook. Currently I am planning to just chop off .js extensions, but then there is a perf impact if I chop off the extension and then it must search all extension.

We have options

Is there an option I am missing that handles this?

[alexander-akait]

You search this TypeStrong/ts-loader#1383

[vjpr]

Thanks, this logic is TS-specific so should not be inside enhanced-resolve as you mention.