Error: jest-haste-map: Haste module naming collision:

Question

I have created a custom npm module (will use xxx instead of its name) and link it manually using npm install.

I tried very hard and searched :

• [Workarounds] Packager unable to resolve module from /Users/node_modules/
• Error: jest-haste-map: @providesModule naming collision when using a local dependency

before raising a question. I would be thankful if someone tell me what wrong with my code or my approach or any error in my code.

When I run react-native run-android following error is raised by metro bundler

Error: jest-haste-map: Haste module naming collision:
  Duplicate module name: react-native
  Paths: E:\cdg-native\CDG\node_modules\react-native-XXX\node_modules\react-native\package.json collides with E:\cdg-native\CDG\node_modules\react-native\package.json

This error is caused by `hasteImpl` returning the same name for different files.

My custom module package.json is

{
  "name": "react-native-xxx",
  "version": "1.0.0",
  "description": "Library to render xxx",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [
    "react native xxx"
  ],
  "author": "Firdous Nath",
  "license": "ISC",
  "peerDependencies": {
    "react": "*",
    "react-native": "*"
  },
  "devDependencies": {
    "react": "^16.6.1",
    "react-native": "^0.57.5",
    "babel-cli": "^6.26.0",
    "babel-plugin-transform-class-properties": "^6.24.1",
    "babel-plugin-transform-object-rest-spread": "^6.26.0",
    "babel-plugin-transform-runtime": "^6.23.0",
    "babel-preset-env": "^1.6.1",
    "babel-preset-react": "^6.24.1"
  }
}

index.js of the custom module is very simple as below

import React from "react";
import { Text } from "react-native";

export default class XXXView extends React.Component {

    render() {
        return (
            <Text> From custom module </Text>
        );
    }
}

file where I am using custom module is

import React from "react";
import {StyleSheet, View} from "react-native";
import XXXView from "react-native-xxx"
//import {XXXView} from "react-native-xxx" -> I tried this as well

export default class App extends React.Component {
    render() {
        return (
            <View style={styles.container}>
                <XXXView/>
            </View>
        )
    }
}

const styles = StyleSheet.create({
    container: {
        flex: 1,
        justifyContent: "center",
        alignItems: "center",
        backgroundColor: "#f5fcff"
    }
});

I tried npm install /absolute/path/to/xxx and it linked module correctly. By correctly I mean I can see react-native-xxx package in nodemodule directory. I did all possible ways but nothing worked.

I also tried but got no success

• yarn add /absolute/path/to/react-native-xxx
• react-native link react-native-xxx
• react-native run-android

Answer 1

Add rn-cli.config.js In the root project

const blacklist = require('metro-config/src/defaults/blacklist');
module.exports = {
 resolver: {
    blacklistRE: blacklist([
        /node_modules\/.*\/node_modules\/react-native\/.*/,
    ])
 },
};

see this issue

Hope it works for you

Answer 2

The error you get indicates that you have two react-native dependencies. One in your main project, one in your xxx module, thus creating a conflict between their package.jsons. seems like if you install a package from a local path, it copies its node_modules directory.

As you already have react-native as peer dependency in your custom module's package.json, try removing E:\cdg-native\CDG\node_modules\react-native-XXX\node_modules, this should solve the conflict.

Answer 3

It looks like you have a 2 different react-native project folders where one is dependent over another (it's getting included as node_module dependency) and it seems you are running your server start ("react-native start") command from the library folder.