ERR_REQUIRE_ESM

[wdamaral]

Hey folks,
I'm playing around with formidable. More like learning its details than anything, as I'm fairly new to Typescript.

I'm facing with an issue that might be a bug or some sort of incompatibility that I can't figure out the reason.
Am I doing something wrong here?

The error states:

C:\Users\wfura\Documents\Projects\formidable\node_modules\ts-node\dist\index.js:842
return old(m, filename);
^
Error [ERR_REQUIRE_ESM]: require() of ES Module C:\Users\wfura\Documents\Projects\formidable\node_modules\formidable\src\index.js from C:\Users\wfura\Documents\Projects\formidable\src\app.ts not supported.
Instead change the require of index.js in C:\Users\wfura\Documents\Projects\formidable\src\app.ts to a dynamic import() which is available in all CommonJS modules.
at require.extensions. [as .js] (C:\Users\wfura\Documents\Projects\formidable\node_modules\ts-node\dist\index.js:842:20)
at Object. (C:\Users\wfura\Documents\Projects\formidable\src\app.ts:7:38)
at m._compile (C:\Users\wfura\Documents\Projects\formidable\node_modules\ts-node\dist\index.js:848:29)
at require.extensions. [as .ts] (C:\Users\wfura\Documents\Projects\formidable\node_modules\ts-node\dist\index.js:850:16)
at phase4 (C:\Users\wfura\Documents\Projects\formidable\node_modules\ts-node\dist\bin.js:414:16)
at bootstrap (C:\Users\wfura\Documents\Projects\formidable\node_modules\ts-node\dist\bin.js:49:12)
at main (C:\Users\wfura\Documents\Projects\formidable\node_modules\ts-node\dist\bin.js:32:12)
at Object. (C:\Users\wfura\Documents\Projects\formidable\node_modules\ts-node\dist\bin.js:526:5) {
code: 'ERR_REQUIRE_ESM'
}

I only have formidable on this project with express. My package.json is as below.

{
  "name": "formidable",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "dev": "nodemon ./src/app.ts"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "express": "^4.18.1",
    "formidable": "^3.2.4"
  },
  "devDependencies": {
    "@types/express": "^4.17.13",
    "@types/formidable": "^2.0.5",
    "@types/node": "^17.0.41",
    "nodemon": "^2.0.16",
    "ts-node": "^10.8.1",
    "typescript": "^4.7.3"
  }
}

tsconfig.json

{
  "compilerOptions": {
    "target": "ES6",
    "module": "commonjs",
    "outDir": "./dist",
    "rootDir": "./src",
    "esModuleInterop": true
  }
}

Finally, the single file in this project.

import express from "express";
import formidable from "formidable";

const app: express.Application = express();


app.post("/file-upload", (req, res, next) => {
  const form = formidable({});
  console.log(req);
  form.parse(req);

  form.on("fileBegin", (name, file) => {
      console.log(file)
  });

  form.on("file", (name, file) => {
      console.log(name)
  });

  res.sendStatus(200)
});

app.listen(3000, () => console.log("listening on 3000"));

[tunnckoCore]

@wdamaral hello there.

For now the v3 version is only ESM compatible (and not CJS/CommonJS, e.g. with requires), so you need to make your project accepting ES Modules. That's by adding "type": "module" in your package.json.