Why i am getting typescript SyntaxError in every d.ts file?

Question

So after i run "node main.js" i'm getting errors in every d.ts file:

declare function addTask(db: any): (params: any) => void;
        ^^^^^^^^

SyntaxError: Unexpected token 'function'
    at Object.compileFunction (vm.js:344:18)
    at wrapSafe (internal/modules/cjs/loader.js:1106:15)
    at Module._compile (internal/modules/cjs/loader.js:1140:27)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1196:10)
    at Module.load (internal/modules/cjs/loader.js:1040:32)
    at Function.Module._load (internal/modules/cjs/loader.js:929:14)
    at Module.require (internal/modules/cjs/loader.js:1080:19)
    at require (internal/modules/cjs/helpers.js:72:18)
    at /home/vdm/dev/reminder/dist/actions/index.js:11:24
    at Array.forEach (<anonymous>)

addTask.ts:

function addTask(db: any) {
  return function (params: any): void {
    db.get('tasks').push(params).write();
  };
}

export = addTask;

addTask.d.ts:

declare function addTask(db: any): (params: any) => void;
export = addTask;

tsconfig.json:

{
  "compilerOptions": {
    "target": "ES6",                          /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', 'ES2018', 'ES2019', 'ES2020', or 'ESNEXT'. */
    "module": "commonjs",                     /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', 'es2020', or 'ESNext'. */
    "declaration": true,                   /* Generates corresponding '.d.ts' file. */
    "outDir": "dist",                        /* Redirect output structure to the directory. */
    "rootDir": "src",                       /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */
    "strict": true,                           /* Enable all strict type-checking options. */
    "esModuleInterop": true,                  /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
    "skipLibCheck": true,                     /* Skip type checking of declaration files. */
    "forceConsistentCasingInFileNames": true  /* Disallow inconsistently-cased references to the same file. */
  }
}

index.ts:

const fs = require('fs');
const path = require('path');

const loader = (db: any) => {
  const modules: {[index: string]:any} = {};
  const files = fs.readdirSync(__dirname);
  files.forEach((file: any) => {
    const modulePath = path.join(__dirname, file);
    const name = path.basename(file, '.js');
    if (name !== 'index') {
      const fn = require(modulePath)(db);
      modules[name] = fn;
    }
  });
  
  return modules;
};

export = loader;

index.js:

"use strict";
const fs = require('fs');
const path = require('path');
const loader = (db) => {
    const modules = {};
    const files = fs.readdirSync(__dirname);
    files.forEach((file) => {
        const modulePath = path.join(__dirname, file);
        const name = path.basename(file, '.js');
        if (name !== 'index') {
            const fn = require(modulePath)(db);
            modules[name] = fn;
        }
    });
    return modules;
};
module.exports = loader;

project structure:

i don't understand why i am getting typescript errors in runtime? looks like node trying to run those d.ts files or idk. How to fix that? ps: if i set declaration: false in tsconfig, error is gone, but i need d.ts files

That's not a typescript error, it looks like you are trying to run a typescript file instead of the compiled javascript. — Jake Holzinger
You haven't posted the index.ts or index.js code, but the stack trace seems to indicate this error is happening when you are requiring the addTask module. See: /home/vdm/dev/reminder/dist/actions/index.js:11:24. — Jake Holzinger
You must filter out the files with .ts extension. Using path.basename(file, 'js') does not do that for you. — Jake Holzinger

Jake Holzinger Jake Holzinger · Accepted Answer · 2020-06-22T21:44:00

You need to filter out the .ts files. NodeJS does not know how to parse TypeScript.

const fs = require('fs');
const path = require('path');

const loader = (db: any) => {
  const modules: {[index: string]:any} = {};
  const files = fs.readdirSync(__dirname);
  files.forEach((file: any) => {
    if (file.endsWith('.js')) {
      const modulePath = path.join(__dirname, file);
      const name = path.basename(file, '.js');
      if (name !== 'index') {
        const fn = require(modulePath)(db);
        modules[name] = fn;
      }
    }
  });
  
  return modules;
};

export = loader;

Why i am getting typescript SyntaxError in every d.ts file?

1 Answers