I'm creating a program to analyze security camera streams and got stuck on the very first line. At the moment my .js file has nothing but the import of node-fetch and it gives me an error message. What am I doing wrong?
Running Ubuntu 20.04.2 LTS in Windows Subsystem for Linux.
Node version:
user@MYLLYTIN:~/CAMSERVER$ node -v
v14.17.6
node-fetch package version:
user@MYLLYTIN:~/CAMSERVER$ npm v node-fetch
node-fetch@3.0.0 | MIT | deps: 2 | versions: 63
A light-weight module that brings Fetch API to node.js
https://github.com/node-fetch/node-fetch
keywords: fetch, http, promise, request, curl, wget, xhr, whatwg
dist
.tarball: https://registry.npmjs.org/node-fetch/-/node-fetch-3.0.0.tgz
.shasum: 79da7146a520036f2c5f644e4a26095f17e411ea
.integrity: sha512-bKMI+C7/T/SPU1lKnbQbwxptpCrG9ashG+VkytmXCPZyuM9jB6VU+hY0oi4lC8LxTtAeWdckNCTa3nrGsAdA3Q==
.unpackedSize: 75.9 kB
dependencies:
data-uri-to-buffer: ^3.0.1 fetch-blob: ^3.1.2
maintainers:
- endless <jimmy@warting.se>
- bitinn <bitinn@gmail.com>
- timothygu <timothygu99@gmail.com>
- akepinski <npm@kepinski.ch>
dist-tags:
latest: 3.0.0 next: 3.0.0-beta.10
published 3 days ago by endless <jimmy@warting.se>
esm package version:
user@MYLLYTIN:~/CAMSERVER$ npm v esm
esm@3.2.25 | MIT | deps: none | versions: 140
Tomorrow's ECMAScript modules today!
https://github.com/standard-things/esm#readme
keywords: commonjs, ecmascript, export, import, modules, node, require
dist
.tarball: https://registry.npmjs.org/esm/-/esm-3.2.25.tgz
.shasum: 342c18c29d56157688ba5ce31f8431fbb795cc10
.integrity: sha512-U1suiZ2oDVWv4zPO56S0NcR5QriEahGtdN2OR6FiOG4WJvcjBVFB0qI4+eKoWFH483PKGuLuu6V8Z4T5g63UVA==
.unpackedSize: 308.6 kB
maintainers:
- jdalton <john.david.dalton@gmail.com>
dist-tags:
latest: 3.2.25
published over a year ago by jdalton <john.david.dalton@gmail.com>
Contents of the .js file (literally nothing but the import):
user@MYLLYTIN:~/CAMSERVER$ cat server.js
import fetch from "node-fetch";
Result:
user@MYLLYTIN:~/CAMSERVER$ node -r esm server.js
/home/user/CAMSERVER/node_modules/node-fetch/src/index.js:1
Error [ERR_REQUIRE_ESM]: Must use import to load ES Module: /home/user/CAMSERVER/node_modules/node-fetch/src/index.js
require() of ES modules is not supported.
require() of /home/user/CAMSERVER/node_modules/node-fetch/src/index.js from /home/user/CAMSERVER/server.js is an ES module file as it is a .js file whose nearest parent package.json contains "type": "module" which defines all .js files in that package scope as ES modules.
Instead rename index.js to end in .cjs, change the requiring code to use import(), or remove "type": "module" from /home/user/CAMSERVER/node_modules/node-fetch/package.json.
at Object.Module._extensions..js (internal/modules/cjs/loader.js:1089:13) {
code: 'ERR_REQUIRE_ESM'
}
user@MYLLYTIN:~/CAMSERVER$
From the Upgrade Guide
node-fetch was converted to be a ESM only package in version 3.0.0-beta.10. node-fetch is an ESM-only module - you are not able to import it with require.
Alternatively, you can use the async import() function from CommonJS to load node-fetch asynchronously:
// mod.cjs
const fetch = (...args) => import('node-fetch').then(({default: fetch}) => fetch(...args));
or you stay on v2 as they say in the README
node-fetchis an ESM-only module - you are not able to import it with require. We recommend you stay on v2 which is built with CommonJS unless you use ESM yourself. We will continue to publish critical bug fixes for it.
EDIT
I saw that in the doc, used it, and the script crashes with :
error TS2556: A spread argument must either have a tuple type or be passed to a rest parameter.
Since you are using typescript you should do something like this
import { RequestInfo, RequestInit } from "node-fetch";
const fetch = (url: RequestInfo, init?: RequestInit) => import("node-fetch").then(({ default: fetch }) => fetch(url, init));
node-fetch v3 is ESM-only: https://github.com/node-fetch/node-fetch#loading-and-configuring-the-module. The esm module you’re adding is for adding ESM compatibility, but it’s unnecessary now that Node 12+ supports ESM natively; and it doesn’t work with ESM-only packages like node-fetch 3+.
To fix your issue:
esm package."type": "module" to your package.json.And that’s it. Then when you run node server.js it should work.
To fix this, I downgraded node-fetch to the latest version 2, which right now is 2.6.6. This is the script I ran:
yarn add node-fetch@^2.6.6
or
npm install node-fetch@^2.6.6
I also added these compiler options:
{
"compilerOptions": { "allowJs": true, "outDir": "./dist" },
}