CODEWITHSUNDEEP
node.jstypescript
Daniele Ricci
Daniele Ricci

Reputation: 15837

ERR_REQUIRE_ESM - TypeScript + nodemon + ts-node + node-fetch

I'm trying to use node-fetch v3 with nodemon + ts-node, but I got all possible errors about ESM. I've tried many combination of type in the package.json file and compilerOptions.target in the tsconfig.json file, but I'm not able to simultaneously compile my script and run it in development mode.

This is my simple script:

import express from "express";
import fetch from "node-fetch";
import json from "json-server";

const app = express();

app.use("/db", json.router("db.json"));

app.use("/test", (req, res) => {
  fetch("http://localhost:3001/db");
  res.json({ ok: true });
});

app.listen(3001);

I need to be able to make it work with following two commands:

tsc && node index.js
nodemon -r ts-node index.ts

How should be package.json and tsconfig.json configured to make both the commands to work?

Please note that the problems start as soon as I add node-fetch to the project.

Upvotes: 6

Views: 4952

Answers (1)

Shahriar Shojib
Shahriar Shojib

Reputation: 927

It is currently very hard to compile typescript to native ESM I recommend downgrading node-fetch to 2.6.5.

Node Fetch started shipping ES Modules since 3.0.0 see here: https://github.com/node-fetch/node-fetch/blob/main/docs/v3-UPGRADE-GUIDE.md#breaking

If you want to go the hard route you can follow this blog: https://2ality.com/2021/06/typescript-esm-nodejs.html

The problem is that you cannot use require('some-module') which is built to be an ESM. Since you're compiling to commonjs modules it will require some transpiling to make them work with ESM.

Typescript is adding nodenext as a module option on typescript 4.5

Upvotes: 11

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