Kevin Powell - Community•9mo ago

Installing a library with JS

Hello, I'm trying to build a demo bar code scanner. I found this library: https://serratus.github.io/quaggaJS/#node-example I've installed Node + Quagga (library) My dependencies are the following:

{
  "name": "bar-code-project",
  "version": "1.0.0",
  "description": "",
  "main": "scan.js",
  "type": "module",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "node": "^21.6.2",
    "quagga": "^0.12.1"
  }
}

{
  "name": "bar-code-project",
  "version": "1.0.0",
  "description": "",
  "main": "scan.js",
  "type": "module",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "node": "^21.6.2",
    "quagga": "^0.12.1"
  }
}

However, when running test script (provided in docs), I get this error

ReferenceError: require is not defined
    at scan.js:71:14

which makes me believe I've installed wrong. Any ideas how to fix this? Sample script ran:

var Quagga = require('quagga');

Quagga.decodeSingle({
    src: "image-abc-123.jpg",
    numOfWorkers: 0,  // Needs to be 0 when used within node
    inputStream: {
        size: 800  // restrict input-size to be 800px in width (long-side)
    },
    decoder: {
        readers: ["code_128_reader"] // List of active readers
    },
}, function(result) {
    if(result.codeResult) {
        console.log("result", result.codeResult.code);
    } else {
        console.log("not detected");
    }
});

var Quagga = require('quagga');

Quagga.decodeSingle({
    src: "image-abc-123.jpg",
    numOfWorkers: 0,  // Needs to be 0 when used within node
    inputStream: {
        size: 800  // restrict input-size to be 800px in width (long-side)
    },
    decoder: {
        readers: ["code_128_reader"] // List of active readers
    },
}, function(result) {
    if(result.codeResult) {
        console.log("result", result.codeResult.code);
    } else {
        console.log("not detected");
    }
});

QuaggaJS, an advanced barcode-reader written in JavaScript

QuaggaJS is an advanced barcode-reader written in JavaScript

18 Replies

Heitor•9mo ago

did you run npm install in your project folder?

MattOP•9mo ago

Yes I did. My script tag also has module attribute

Heitor•9mo ago

oh, i tested it with this in the first line and it worked, maybe try it var Quagga = require('quagga').default;

MattOP•9mo ago

Same issue Which commands did you run? @Heitor is this because I'm running node in browser without express?

Heitor•9mo ago

not sure, I installed the library with npm, created a file index.js with the example and ran "node index.js" in the terminal

MattOP•9mo ago

Hmm I'm lost right now keep getting this error ReferenceError: document is not defined when running node scan.js

MattOP•9mo ago

I have node

MattOP•9mo ago

MattOP•9mo ago

https://www.geeksforgeeks.org/how-to-run-node-js-server/

GeeksforGeeks

How to run Node Server ? - GeeksforGeeks

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MattOP•9mo ago

Following these exact commands + sample code still gives me errors

ReferenceError: require is not defined in ES module scope, you can use import instead
This file is being treated as an ES module because it has a '.js' file extension and contains "type": "module". To treat it as a CommonJS script, rename it to use the '.cjs' file extension.

ReferenceError: require is not defined in ES module scope, you can use import instead
This file is being treated as an ES module because it has a '.js' file extension and contains "type": "module". To treat it as a CommonJS script, rename it to use the '.cjs' file extension.

Heitor•9mo ago

maybe try changing the require to ES6 module import import Quagga from 'quagga';

MattOP•9mo ago

@Heitor What npm commands did you run?

Heitor•9mo ago

just npm i quagga and before i started the project, with npm init -y

MattOP•9mo ago

hmm ive no idea lol do you have node isntalled?

Heitor•9mo ago

yeah i have node, not sure what is happening there, sorry i could not help much 😕

MattOP•9mo ago

No worries! Thank you @Heitor

firxworx•9mo ago

@Matt quagga is a browser library per its readme so your issue makes sense. Your error gives it away: any time you see a mention of document not existing you are definitely trying to run something written for browser (where there's a document global e.g. document.querySelector("#heroSection")) in a server-side environment (like NodeJS) where no such thing exists. Hence the error: code is trying to reference it and its not defined.

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