Uncaught TypeError: Cannot read property 'prototype' of undefined [xml2js]

[TedChenNZ]

When I try to use xml2js I get the following error in the browser.

http://localhost:8080/web_modules/xml2js.js [:516:195]
TypeError: Cannot read property 'prototype' of undefined
    at extend (http://localhost:8080/web_modules/xml2js.js:516:195)
    at http://localhost:8080/web_modules/xml2js.js:530:5
    at http://localhost:8080/web_modules/xml2js.js:808:5
    at http://localhost:8080/web_modules/xml2js.js:810:4
    at createCommonjsModule (http://localhost:8080/web_modules/common/_commonjsHelpers-6d0ad781.js:10:5)
    at http://localhost:8080/web_modules/xml2js.js:512:18

I added this to the snowpack.config.js without much success.

  installOptions: {
    polyfillNode: true, // needed to get the build to work in the first place
    namedExports: ['xml2js'] // tried this but it didn't seem to affect anything
  },

To reproduce

npx create-snowpack-app new-dir --template @snowpack/app-template-react-typescript
cd new-dir
npm i xml2js
npm i @types/xml2js -D

In App.tsx add (with parseStringPromise somewhere above the return in the App function)

import { parseStringPromise } from 'xml2js';
...

parseStringPromise('<test>xml</text>').then(console.log);

npm start

[daydayhappychao]

same question.

[taylorfsteele]

Having a similar issue with the 'jsonwebtoken' npm package in a typescript react application:

http://localhost:8080/web_modules/jsonwebtoken.js [:2530:29]
TypeError: Object prototype may only be an Object or null: undefined
    at Function.create (<anonymous>)
    at Object.inherits (http://localhost:8080/web_modules/jsonwebtoken.js:2530:29)
    at http://localhost:8080/web_modules/jsonwebtoken.js:5073:8
    

Same install options as well:

  installOptions: {
    /* ... */
    polyfillNode: true,
  },
  

Not sure if this is something that needs to be an Issue or if I'm doing something wrong in the config

[bmorashad]

Having the almost the same issue with jsonwebtoken except it says jws instaed of jsonwebtoken

[Reeska]

In my case I've replaced jsonwebtoken by jwt-decode (I only need to decode some JWT) and it works fine.

[roblframpton]

Similar for me, I get TypeError: superCtor.prototype is not an object or null in jws when I'm using jsonwebtoken

[computeone]

antlr4ts same question.

[AJamesPhillips]

@computeone is issue #3317 related to your problem?