require() is generated in JS although there's no runtime code

[Llorx]

🔎 Search Terms

require generated const enum namespace require generated namespace require const enum namespace require "export import" require

⏯ Playground Link

Multiple files, so can't use playground

💻 Code

// file1.ts
export namespace MyOtherNamespace {
    export const enum Yay {
        OK,
        KO
    }
}

// file2.ts
import { MyOtherNamespace } from "./file1";
export namespace MyNamespace {
    export import NS2 = MyOtherNamespace;
}

import { MyNamespace } from "./file2.ts";

const val = MyNamespace.NS2.Yay.KO

// Compiled code
const file2_1 = require("./file2"); // notice the variable name which is just "filename_1", as it is not used anywhere
const val = 1;

🙁 Actual behavior

Compiling an unused const file2_1 = require("./file2"); line

🙂 Expected behavior

Do not compile unused line.

Additional information about the issue

The problem is that this file is a types file, so it is installed only in develpment environment (npm install -D xxx) so in runtime it is failing because it can't find the required module.

If I modify the MyNamespace namespace to directly export a namespace instead of doing an export import it works, but we have a lot of namespaces so we have them separated into files, and couldn't find another way to export an imported namespace inside another namespace.

[Llorx]

NOTE: Now I'm importing file1.ts directly to access to the const enum.

[RyanCavanaugh]

For consistency, imports are generated if there's an apparent value reference, even if it's inlined at the end. You can use import type if you don't want this to appear.

[Llorx]

@RyanCavanaugh That doesn't work because it complains that you can't use a const enum in runtime when imprting using import type (although is a const enum).

Also, if I remove the "export import" and just add the namespace inline, this problem doesn't happen. It seems like a bug when using "export import" because that's the key difference that creates this problem.

[andrewbranch]

@Llorx what compiler options are you using?

[Llorx]

@andrewbranch This is my tsconfig:

{
    "compilerOptions": {
        "target": "es2020",
        "lib": ["esnext"],
        "module": "commonjs",
        "allowJs": true,
        "allowSyntheticDefaultImports": true,
        "moduleResolution": "node",
        "noImplicitAny": true,
        "strictNullChecks": true,
        "removeComments": true,
        "sourceMap": true,
        "esModuleInterop": true,
        "strictBindCallApply": true,
        "strictFunctionTypes": true,
        "outDir": "./lib"
    },
    "include": [
        "./src/index.ts"
    ]
}