File declaration for modules within modules

I'm currently working on a project that includes a Node JS module located at foo/bar.js. As I'm developing a TypeScript module in src/mymod.ts that needs to import foo/bar.js, I'm facing a challenge in creating a declarations file for the foo/bar.js module. Where should I place this declarations file?

My attempt at placing a declarations file in foo/bar.d.ts resulted in an error when I tried to

import * as bar from "../foo/bar"
in my TypeScript module:

File '/tmp/my_proj/foo/bar.d.ts' is not a module.

Below is a snippet of my tsconfig.json file:

{
  "compilerOptions": {
    "allowJs": true,
    "outDir": "./dist/",
    "target": "es2017",
    "module": "commonjs",
    "strictNullChecks": true
  },
  "include": [
    "./src/"
  ]
}

Here's a snippet from my declaration file:

// Type definitions for bar
declare module "bar" {
  function fun1(n: number) : number;
  function fun2(n: number) : number;
  function fun3(n: number) : number;
}

Answer №1

After reviewing the issue, I found that by modifying the declarations file as shown below, the problem gets resolved:

export function fun1(n: number) : number;
export function fun2(n: number) : number;
export function fun3(n: number) : number;

This solution dawned on me after reading a comment by @Gerrit0. If anyone can provide a more detailed answer with explanations, I am open to updating my response.

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