Typescript imports have wrong file extension

[dburriss]

Description

When running fable the generated TS files link to JS files that do not exist.

Repro code

https://github.com/dburriss/haya-net/tree/typescript-support/src/Haya.Deno

Note: The deno project is referencing files in another project. Was hoping there was a better way to do this but could not think of anything.

Expected and actual results

When running:

dotnet fable --outDir ./ --lang ts

The generated .ts files contain imports like the following:

import { toString, Record, Union } from "../fable_modules/fable-library-ts.4.24.0/Types.js";
import { bool_type, record_type, string_type, union_type, TypeInfo } from "../fable_modules/fable-library-ts.4.24.0/Reflection.js";
import { IComparable, IEquatable } from "../fable_modules/fable-library-ts.4.24.0/Util.js";
import { StringBuilder__AppendLine, StringBuilder__AppendLine_Z721C83C5, StringBuilder__Append_Z721C83C5, StringBuilder_$ctor_Z721C83C5, StringBuilder_$ctor } from "../fable_modules/fable-library-ts.4.24.0/System.Text.js";
import { FSharpList, fold } from "../fable_modules/fable-library-ts.4.24.0/List.js";

The file ../fable_modules/fable-library-ts.4.24.0/Types.js does not exist though, instead ../fable_modules/fable-library-ts.4.24.0/Types.ts exists (which is what I expect). So the imports are generated expecting .js, when they should be expecting .ts.

Related information

• Fable version: 4.24.0 (was happening on 4.22.0 too)
• Operating system: OSX

[MangelMaxime]

Similar to #3686 (comment)

To allow people consuming Fable => TS with runtimes like Deno we will need to add a new compiler flag.