compiling a typescript file produces empty object

[Dmitry-N-Medvedev]

good morning, nice community!

I cannot understand why a compilation of a typescript file gives me a javascript file with an empty object.
Desperately need any ideas/hints/etc. Much appreciated any in advance!

The following types.ts

//types.ts

import { ByteBuffer } from './byte-buffer.js'
import { Builder } from './builder.js'

export type Offset = number;

export type Table = {
  bb: ByteBuffer
  bb_pos: number
};

export interface IGeneratedObject {
  pack(builder:Builder): Offset
}

export interface IUnpackableObject<T> {
  unpack(): T
}

...is translated to the types.js:

// types.js

export { };

the following command has been used to run the compilation:

node node_modules/@swc/cli/bin/swc.js ./types.ts --out-dir ./out --sync --config-file .swcrc

This is the .swcrc file used as a config:

// .swcrc

{
  "$schema": "https://swc.rs/schema.json",
  "exclude": [
    "node_modules"
  ],
  "jsc": {
    "parser": {
      "syntax": "typescript",
      "tsx": false,
      "decorators": false,
      "dynamicImport": true
    },
    "transform": {},
    "target": "es2022",
    "loose": false,
    "externalHelpers": false,
    "keepClassNames": true,
    "baseUrl": "./"
  },
  "minify": false,
  "isModule": true,
  "module": {
    "type": "es6",
    "strict": false,
    "strictMode": false,
    "lazy": false,
    "noInterop": false,
    "ignoreDynamic": true,
    "importInterop": "swc",
    "preserveImportMeta": true,
    "resolveFully": true
  }
}

[kwonoj]

Everything you exported in the module is type or interface, which is expected to be removed after trnaspiling into javascript.

[Dmitry-N-Medvedev]

aha, understood! thank you.

then I have a much bigger problem. In the flatbuffers.js file there is an import that references the types.js file:

// flatbuffers.js

export { SIZEOF_SHORT } from "./constants.js";
export { SIZEOF_INT } from "./constants.js";
export { FILE_IDENTIFIER_LENGTH } from "./constants.js";
export { SIZE_PREFIX_LENGTH } from "./constants.js";
export { Table, Offset, IGeneratedObject, IUnpackableObject } from "./types.js";
export { int32, float32, float64, isLittleEndian } from "./utils.js";
export { Encoding } from "./encoding.js";
export { Builder } from "./builder.js";
export { ByteBuffer } from "./byte-buffer.js";

Now, when I have an empty object exported from the types.js file, the Table, Offset, etc aren't going to be found.

I am obviously doing something very naive or even stupid and I have no idea how to even approach this case.

@kwonoj , could you please share you thoughts on this?

[kdy1]

You can use type-only import/export specifiers for the imports.

[Dmitry-N-Medvedev]

thank you @kdy1 :)

You might have already noticed I am quite new to typescript. Could you please explain your suggestion in a slightly different words or point me to a respective article? Much appreciated!

[kdy1]

Ah, I was on mobile as it was about time to sleep.

export type { Table, Offset, IGeneratedObject, IUnpackableObject } from "./types.js";

or

export { type Table, type Offset, type IGeneratedObject, type IUnpackableObject } from "./types.js";

will work