Can't resolve module (not found) in React.js - javascript

I can't believe that I'm asking an obvious question, but I still get the error in console log.
Console says that it can't find the module in the directory, but I've checked at least 10 times for typos. Anyways, here's the component code.
I want to render Header in root
import React, { Component } from 'react'
import Header from './src/components/header/header'
import logo from './logo.svg'
import './App.css'
class App extends Component {
render() {
return (
<Header/>
);
}
}
export default App;
This is the Header component
import React, { Component } from 'react'
import ReactDOM from 'react-dom'
import navBar from './src/components/header/navBar'
import './src/css/header.css'
class Header extends Component {
render() {
return {
<div>
<div id="particles-js"></div>
<navBar/>
<Title/>
</div>
};
}
}
ReactDOM.render(<Header/>, document.getElementById('header'));
I've checked at least 10 times that the module is at this location ./src/components/header/header, and it is (folder "header" contains "header.js").
Yet, React still throws this error:
Failed to compile
./src/App.js
Module not found: Can't resolve './src/components/header/header' in '/home/wiseman/Desktop/React_Components/github-portfolio/src'
npm test says the same thing.

The way we usually use import is based on relative path.
. and .. are similar to how we use to navigate in terminal like cd .. to go out of directory and mv ~/file . to move a file to current directory.
my-app/
node_modules/
package.json
src/
containers/card.js
components/header.js
App.js
index.js
In your case, App.js is in src/ directory while header.js is in src/components. To import you would do import Header from './components/header'. This roughly translate to in my current directory, find the components folder that contain a header file.
Now, if from header.js, you need to import something from card, you would do this. import Card from '../containers/card'. This translate to, move out of my current directory, look for a folder name containers that have a card file.
As for import React, { Component } from 'react', this does not start with a ./ or ../ or / therefore node will start looking for the module in the node_modules in a specific order till react is found. For a more detail understanding, it can be read here.

If you create an application with react-create-app, don't forget set environment variable:
NODE_PATH=./src
Or add to .env file to your root folder;

Deleted the package-lock.json file & then ran
npm install
Read further

in my case, The error message was
Module not found: Error: Can't resolve '/components/body
While everything was in the correct directory.
I found that renaming body.jsx to body.js resolve the issue!
So I added this code in webpack.config.js to resolve jsx as js
module.exports = {
//...
resolve: {
extensions: ['.js', '.jsx']
}
};
And then build error gone!

Adding NODE_PATH as environment variable in .env is deprecated and is replaced by adding "baseUrl": "./src", to compilerOptions in jsconfig.json or tsconfig.json.
Reference

I think its the double use of header. I just tried something similar myself and also caused issues. I capitalized my component file to match the others and it worked.
import Header from './src/components/header/header';
Should be
import Header from './src/components/header/Header';

There is a better way you can handle the import of modules in your React App.
Consider doing this:
Add a jsconfig.json file to your base folder. That is the same folder containing your package.json. Next define your base URL imports in it:
//jsconfig.json
{
"compilerOptions": {
"baseUrl": "./src"
}
}
Now rather than calling ../../ you can easily do this instead:
import navBar from 'components/header/navBar'
import 'css/header.css'
Notice that 'components/' is different from '../components/'
It's neater this way.
But if you want to import files in the same directory you can do this also:
import logo from './logo.svg'

I solved by putting the file extension
import MyComponent from "src/components/MyComponent";
to
import MyComponent from "src/components/MyComponent.tsx";

I had a similar issue.
Cause:
import HomeComponent from "components/HomeComponent";
Solution:
import HomeComponent from "./components/HomeComponent";
NOTE: ./ was before components. You can read #Zac Kwan's post above on how to use import

You can try to execute 'npm install' in the app folder. This might also solve the problem. It worked for me.

I faced the same issue when I created a new react app, I tried all options in https://github.com/facebook/create-react-app/issues/2534 but it didn't help. I had to change the port for the new app and then it worked. By default, apps use the port 3000.I changed the port to 8001 in package.json as follows:
"scripts": {
"start": "PORT=8001 react-scripts start",
"build": "react-scripts build",
"test": "react-scripts test",
"eject": "react-scripts eject"
},

If you are using create-react-app, and have just added typescript to it, check whether a tsconfig.json has been auto-generated for you. The CRA docs say that it should be, but there seems to be a bug at the moment where it is not being generated.
If the tsconfig.json is missing, there's a few ways to create one yourself.
Copy one off the internet or from another repo
npx tsc --init
Create a fresh project somewhere else using npx create-react-app my-ts-proj --template typescript and then copy the tsconfig over from there

you should change import Header from './src/components/header/header' to
import Header from '../src/components/header/header'

You need to be in project folder, if you are in src or public you have to come out of those folders. Suppose your react-project name is 'hello-react' then cd hello-react

I was facing the same problem and I resolved it.
See if your index.js file is in src folder, then what ever file you are importing, the folder containing that must also be inside the src folder.
That means if your components folder is outside the src folder, just drag it inside the src folder in your editor because the files outside of src folder are not imported.
Then you shall be able to import using ./components/header/header(in this case)

For me, I had the input correct but npm start can be buggy (at least using it with Hyper terminal on Windows and Linux). If I move files to different folders, npm start doesn't pick up on these changes. I need to cancel npm start process, make the move, save and then run npm start and it will see the files now.

replace ReactDOM.render(<Header/>, document.getElementById('header')); by export default Header in Header.js

I just had this issue from auto-importing a component, no type or webpack config issues.
What fixed it was changing the import from relative to the app root directory to relative to the file:
import MyComponent from "src/components/MyComponent";
to
import MyComponent from "../components/MyComponent";
If you're getting this from Visual Studio Code auto-importing via the shortest route, you can change it so it imports relatively. By going here:
menu File → Preferences → Settings → User Settings,
"typescript.preferences.importModuleSpecifier": "relative"

It is working for me just (./) no need src here
import Header from './components/header/header'

You might be importing .tsx file inside a .js file. Ensure that if you are working on a javascript source, you have extensions .js or .jsx not .tsx :)

In my case I rename a component file, an VS Code add the below line of code for me:
import React, { Component } from "./node_modules/react";
So I fixed by removing the: ./node_modules/
import React, { Component } from "react";
Cheers!

I think it may help you-
Read your error carefully-./src/App.js
Module not found: Can't resolve './src/components/header/header' in '/home/wiseman/Desktop/React_Components/github-portfolio/src'
just write- ./header/header instead ./src/components/header/header in App.js
if it doesnt work try to change header file name may be head

Check for the import statements.It should be ended with semicolon. If you miss any, you will get this error.
Also check whether following import statement added in you component.
import { threadId } from 'worker_threads';
If so remove that line. It works for me.

Related

How to create, install and import local typescript package

I'm trying to make a package in typescript, this one in particular. But after installing it locally in my project with yarn add file:../parascan-js, I can't import the modules correctly.
I expect import options for my package to be parascan/components/* (name changed from uikit) but what I see are the file/folders in the root such as src, dist, tsconfig etc. I want to be able to import with
import {Table} from "parascan/components/info"
Instead of this
import Table from "parascan/src/components/info/Table"
I've tried building dist folder with tsc and babel. Made some changes to package.json by adding type: module and module: dist/index.js but nothing worked.
Another way to look at this problem is using a generic common package like #chakra-ui/react as example. Text are imported with:
import { Text } from #chakra-ui/react
And not:
import { Text } from #chakra-ui/react/src/index
//or
//import { Text } from #chakra-ui/react/dist/index
I'm new to js/ts, so articles on how to create packages would be helpful.

Next.js imports from root directory: is it valid to start an import with a slash?

This import works, but I can't find any documentation saying that it's valid:
// rather than do a crazy nested import like this
import { myUtil } from '../../../../../lib/utils'
// this appears to work just fine
import { myUtil } from '/lib/utils'
I see where the official answer is to set up a config file with a # alias, so I suppose I will just do that to be compliant. Just thought it was curious that this import worked just fine. I am using the default configuration for a Next.js project set up with create-next-app
Not sure if this is your case, but if the top folder is in the root directory, you can use this
import { myUtil } from './lib/utils'
I'm guessing that's what's happening, even though you don't have the period in yours.

Import more than one class from node_modules

I'm currently developing a package, and inside my package repository I have the following structure:
src
- Requests.js
- Constants.js
package.json
Inside my package.json, I have the following:
{
"name": "package-name",
"version": "1.0.0",
"main": "src/Requests"
}
Then inside my project, I do the following to retrieve my module:
import Requests from 'package-name';
Now what I'm trying to achieve is to import the Constants class from the package. However, when I do the following, I get a compiled error that it cannot locate the class.
import Constants from 'package-name/Constants';
To get it working, I have to do but I don't want to have the /src in the import path.
import Constants from 'package-name/src/Constants';
I've tried to change the main in my package.json to the directory, but it's still not working:
"main": "src/"
Right, this is not a bug, just how node imports are handled by your bundler. There are many solutions to this problem, here are a couple:
The most user friendly is to have your publish command copy those components to the root directory and then publish. That way you'll be able to import like you say, import Constants from 'package-name/Constants'. It's only slightly inconvenient for you as a developer but a script should be able to clean up after the publish command succeeds.
An alternate solution is to have a third file, maybe call it index.js that looks somewhat like this:
import Requests from './Requests';
import Constants from './Constants';
export default {
Requests,
Constants,
};
This will allow you to import like this (don't forget to change your package.json to have "main": "src/index.js"):
import { Requests, Constants } from 'package-name';
The only reason I would shy away from this approach is that when this import statement is handled by the bundler, ALL components are imported, even if you only need one of them. It could make your bundle larger if your library contains many different components.

NodeJS require/import module from higher level directory

I am using node v9.2.0. Want to load module located in higher level directory.
Here is minimal example: https://github.com/skkap/es6importtest
Suppose I have following dir structure:
/common/
index.mjs
/app/
app.mjs
/node_modules/
package.json
index.mjs contains some logic and also imports some npm module, like graphql.
import graphql from 'graphql'
...
export default graphql
I want to import common/index.mjs module from app.js.
import common from '../common/'
And get the following error:
Error: Cannot find module graphql
Any ideas where the problem is?
I checked, it also works the same wat with require(): https://github.com/skkap/es6importtest/tree/master/requireTest
P.S. Please do not recommend using npm packages or webpack for that, this question is about the particular problem described above.

Importing ES6 modules in deep directories

Given this directory tree:
components
foo
index.js
bar
index.js
Using babel es6, I would like to do this:
import Foo from "./components/foo"
import Bar from "./components/foo/bar"
But it errors with Module build failed: Error: ENOENT: no such file or directory, open '/Users/jemminger/Development/whatever/components/foo/bar.js'
The only way I can get it to work is this:
import Foo from "./components/foo"
import Bar from "./components/foo/bar/index"
or
import Foo from "./components/foo"
import Bar from "./components/foo/bar/"
According to https://nodejs.org/api/modules.html#modules_folders_as_modules I should be able to load the index.js file of a directory by default, which happens for foo but not bar.
Is this expected behavior?
Nodejs imports your files realatively, so you always need to care about current path. If you want to start your import path from the same point, try to use webpack. It has resolve.root option, which do exactly what you want. Just set your components root:
resolve: {
root: [
__dirname
]
}
I am assuming that webpack.config.js will be placed next to components dir. Then you can do imports as you want, but without leading ./:
import Foo from "components/foo"
import Bar from "components/foo/bar"
Be aware that now you have collission between npm-module components and your file. Your code will have priority in that case.
So, I'm not sure what the cause of the problem was, but in attempting to replicate the issue today in the same project, it's working as expected. Perhaps just the fact that webpack-dev-server was restarted fixed it. Apparently I can't computer.

Categories