React native package main field related error.

[cmnstmntmn]

Hei,

I'm trying to plug supertruct to a react-native app, but i'm getting this error

error: Error: While trying to resolve module `superstruct` from file `validation.js`, the package `node_modules/superstruct/package.json` was successfully found. 
However, this package itself specifies a `main` module field that could not be resolved (`node_modules/superstruct/index.cjs`. Indeed, none of these files exist:

[cmnstmntmn]

any workarounds for this ?

[cmnstmntmn]

i found this

[roccomuso]

any news on this?

[rhythnic]

package.json is using type:module. For recent versions of Node.js, this means that the entrypoint to the module should be an ECMAScript module; however, main is set to a CommonJS file. This makes Superstruct unusable in any Node.js package of type:module. It's possible to support both ECMAScript modules and CommonJS by using conditional exports.

// package.json
{
  // keep pointing main to cjs for legacy versions of node.js
  "main": "./lib/index.cjs",
  // use conditional exports for recent versions of node.js
  "exports": {
    "import": "./lib/index.es.js",
    "require": "./lib/index.cjs"
  },
  "type": "module"
}

[isnifer]

@rhythnic why did you mention Node.js? The question was about React-Native. Your PR does not help to fix superstruct for RN. @ianstormtaylor too early to close this issue.

[isnifer]

But this config for metro bundler helped me:

// https://github.com/ioveracker/demo-react-native-emotion/blob/master/metro.config.js

const { getDefaultConfig } = require('metro-config');

module.exports = (async () => {
    const {
        resolver: { sourceExts },
    } = await getDefaultConfig();
    return {
        resolver: {
            // Add cjs extension so stylis will load.
            sourceExts: [...sourceExts, 'cjs'],
        },
        transformer: {
            getTransformOptions: async () => ({
                transform: {
                    experimentalImportSupport: false,
                    inlineRequires: false,
                },
            }),
        },
    };
})();

[gabrielgrover]

I am using expo for my react native project and this worked for me

const { getDefaultConfig } = require('@expo/metro-config');

const defaultConfig = getDefaultConfig(__dirname);

module.exports = {
  resolver: {
    sourceExts: [...defaultConfig.resolver.sourceExts, 'cjs'],
  },
};

[leolangen]

We have a different version of metro-config in our project, using RN version 0.61.2. The following worked for me

...
const defaultSourceExts = require('metro-config/src/defaults/defaults').sourceExts 

module.exports = {
  ...
  resolver: {
    sourceExts: [...defaultSourceExts, 'cjs'],
    ...
  }
}

[Thanaen]

Hello !
Question: why was the issue closed? The problem still exists today, just create a new react project and add the package to reproduce it!

[isnifer]

@Thanaen man, just read a comment above yours

[Thanaen]

@Thanaen man, just read a comment above yours

Hello @isnifer ,
If we need to modify a react-native configuration file to make the package work, can we consider the issue resolved? 😕

[isnifer]

@Thanaen yes. Author just decided to use "standard" extension for non es-modules files.
Anyway, I don't care cause I decided don't use this package

[matomesc]

I'm getting the following error after using the workaround above using react-native 0.69.5 and expo