Am using a react application without router settings. I want to build my sitemap.xml file. I tried some modules like sitemap.js, react-router-sitemap, sitemap-generator. But these module are throwing error as fs module is missing. I installed fs module via npm install --save. But it is still showing the error.
I found in some forums to add the below code in webpack.config file.
node: {
fs: "empty"
}
Am not sure where this file is. I couldn't find them nside the sitemap related modules.
Please help me to resolve this. Am new to react.
Here is my folder structure.
create next.config.js and put below code. It works fine for me.
next.config.js
module.exports = {
webpack: (config, { buildId, dev, isServer, defaultLoaders, webpack }) => {
// Note: we provide webpack above so you should not `require` it
// Perform customizations to webpack config
// Important: return the modified config
// Example using webpack option
//config.plugins.push(new webpack.IgnorePlugin(/\/__tests__\//))
config.node = {fs:"empty"}
return config
},
webpackDevMiddleware: config => {
// Perform customizations to webpack dev middleware config
// Important: return the modified config
return config
},
}
Related
How could I add a script to my package.json file that would allow me to dynamically use a local file instead of a package version based on an environment variable?
"dependencies": {
"dynamic-dependency": "$(process.env.NODE_ENV !== 'dev' ? '^1.0.7' : 'file:../local-path-to-package')"
}
You can't do this in package.json, which is non-executable JSON file. The JSON variant used in package.json doesn't even support comments :). The purpose of package.json is to specify which dependencies are installed into node_modules, and that's it. With those dependencies installed, they can be used by Node at runtime, which locates them using the module resolution algorithm:
If the module identifier passed to require() is not a core module, and does not begin with '/', '../', or './', then Node.js starts at the parent directory of the current module, and adds /node_modules, and attempts to load the module from that location. Node.js will not append node_modules to a path already ending in node_modules.
So you can't use NPM/package.json for this. But, I see that you tagged your question with React, so if you are using Webpack, you can solve this issue in your Webpack config. This can be done with resolve.alias:
const path = require('path');
module.exports = {
//...
resolve: {
alias: {
'dynamic-dependency': process.env.NODE_ENV !== 'dev' ? 'dynamic-dependency' : path.resolve(__dirname, '../local-path-to-package'),
},
},
};
I have not used other JS bundlers, but I would have to think Parcel/Rollup etc support this kind of configuration as well.
I try to import a node module inside an Angular 8 web worker, but get an compile error 'Cannot find module'. Anyone know how to solve this?
I created a new worker inside my electron project with ng generate web-worker app, like described in the above mentioned ng documentation.
All works fine until i add some import like path or fs-extra e.g.:
/// <reference lib="webworker" />
import * as path from 'path';
addEventListener('message', ({ data }) => {
console.log(path.resolve('/'))
const response = `worker response to ${data}`;
postMessage(response);
});
This import works fine in any other ts component but inside the web worker i get a compile error with this message e.g.
Error: app/app.worker.ts:3:23 - error TS2307: Cannot find module 'path'.
How can i fix this? Maybe i need some additional parameter in the generated tsconfig.worker.json?
To reproduce the error, run:
$ git clone https://github.com/hoefling/stackoverflow-57774039
$ cd stackoverflow-57774039
$ yarn build
Or check out the project's build log on Travis.
Note:
1) I only found this as a similar problem, but the answer handles only custom modules.
2) I tested the same import with a minimal electron seed which uses web workers and it worked, but this example uses plain java script without angular.
1. TypeScript error
As you've noticed the first error is a TypeScript error. Looking at the tsconfig.worker.json I've found that it sets types to an empty array:
{
"compilerOptions": {
"types": [],
// ...
}
// ...
}
Specifying types turns off the automatic inclusion of #types packages. Which is a problem in this case because path has its type definitions in #types/node.
So let's fix that by explicitly adding node to the types array:
{
"compilerOptions": {
"types": [
"node"
],
// ...
}
// ...
}
This fixes the TypeScript error, however trying to build again we're greeted with a very similar error. This time from Webpack directly.
2. Webpack error
ERROR in ./src/app/app.worker.ts (./node_modules/worker-plugin/dist/loader.js!./src/app/app.worker.ts)
Module build failed (from ./node_modules/worker-plugin/dist/loader.js):
ModuleNotFoundError: Module not found: Error: Can't resolve 'path' in './src/app'
To figure this one out we need to dig quite a lot deeper...
Why it works everywhere else
First it's important to understand why importing path works in all the other modules. Webpack has the concept of targets (web, node, etc). Webpack uses this target to decide which default options and plugins to use.
Ordinarily the target of a Angular application using #angular-devkit/build-angular:browser would be web. However in your case, the postinstall:electron script actually patches node_modules to change that:
postinstall.js (parts omitted for brevity)
const f_angular = 'node_modules/#angular-devkit/build-angular/src/angular-cli-files/models/webpack-configs/browser.js';
fs.readFile(f_angular, 'utf8', function (err, data) {
var result = data.replace(/target: "electron-renderer",/g, '');
var result = result.replace(/target: "web",/g, '');
var result = result.replace(/return \{/g, 'return {target: "electron-renderer",');
fs.writeFile(f_angular, result, 'utf8');
});
The target electron-renderer is treated by Webpack similarily to node. Especially interesting for us: It adds the NodeTargetPlugin by default.
What does that plugin do, you wonder? It adds all known built in Node.js modules as externals. When building the application, Webpack will not attempt to bundle externals. Instead they are resolved using require at runtime. This is what makes importing path work, even though it's not installed as a module known to Webpack.
Why it doesn't work for the worker
The worker is compiled separately using the WorkerPlugin. In their documentation they state:
By default, WorkerPlugin doesn't run any of your configured Webpack plugins when bundling worker code - this avoids running things like html-webpack-plugin twice. For cases where it's necessary to apply a plugin to Worker code, use the plugins option.
Looking at the usage of WorkerPlugin deep within #angular-devkit we see the following:
#angular-devkit/src/angular-cli-files/models/webpack-configs/worker.js (simplified)
new WorkerPlugin({
globalObject: false,
plugins: [
getTypescriptWorkerPlugin(wco, workerTsConfigPath)
],
})
As we can see it uses the plugins option, but only for a single plugin which is responsible for the TypeScript compilation. This way the default plugins, configured by Webpack, including NodeTargetPlugin get lost and are not used for the worker.
Solution
To fix this we have to modify the Webpack config. And to do that we'll use #angular-builders/custom-webpack. Go ahead and install that package.
Next, open angular.json and update projects > angular-electron > architect > build:
"build": {
"builder": "#angular-builders/custom-webpack:browser",
"options": {
"customWebpackConfig": {
"path": "./extra-webpack.config.js"
}
// existing options
}
}
Repeat the same for serve.
Now, create extra-webpack.config.js in the same directory as angular.json:
const WorkerPlugin = require('worker-plugin');
const NodeTargetPlugin = require('webpack/lib/node/NodeTargetPlugin');
module.exports = (config, options) => {
let workerPlugin = config.plugins.find(p => p instanceof WorkerPlugin);
if (workerPlugin) {
workerPlugin.options.plugins.push(new NodeTargetPlugin());
}
return config;
};
The file exports a function which will be called by #angular-builders/custom-webpack with the existing Webpack config object. We can then search all plugins for an instance of the WorkerPlugin and patch its options adding the NodeTargetPlugin.
In NodeJS I have:
const fs = require('fs');
if (!fs.existsSync("some_path")) {
...
}
But I get the error:
TypeError: fs.existsSync is not a function
After doing some searching, I read that Webpack brings its own require which clobbers node.js's require, so when you require a node.js core module that webpack can't resolve to one of your files or dependencies, it throws.
(My stack trace includes __webpack_require__)
But how can I fix it?
I was facing the same Error like TypeError: fs.existsSync is not a function
So, I figured out that one extra line was added automatically which was creating this issue in import.
after removing this line from import
import { TRUE } from "node-sass";
the issue has been resolved.
I had the same error that you have. Your vscode might have added a new module to your js file. Remove that module and your app should work just fine.
You can allow webpack to use the Node's require and include fs etc. by targeting node in the config:
module.exports = {
entry: './src/main.js',
target: 'node',
output: {
path: path.join(__dirname, 'build'),
filename: 'backend.js'
}
}
As described here: https://webpack.js.org/concepts/targets/ and https://webpack.js.org/configuration/target/
I was working on an electron application, I wanted to send a message from node and get in on the react side, but I was having that same issue when requiring ipcRenderer from electron, I tried
import { ipcRenderer } from 'electron';
and
const { ipceRenderer } = require('electron') This leads to an error due to webpack transforming node's require to its own webpack_require. See more info here
What worked for me was to use
const {ipcRenderer} = window.require('electron'); on the react side/renderer side from electron
In my case, I forgot that I'd only imported the promises API, const fs = require("fs").promises, which doesn't have exist or existsSync functions in Node 17.4.0.
To use exist or existsSync, make sure you've imported fs using the sync API (const fs = require("fs")).
Note: I'm adding this answer as a possible solution for future visitors to a canonical thread for the error, not OP who appears to have required fs correctly.
It is nothing to worry about, check your code for something like import { types } from "node-sass";, it would have mistakenly and automatically imported without you know. Remove that line, and everything should work perfectly.
Even if it is not type, it is something from node-sass in your node_modules file, and you can't edit that file.
So look for and remove import { types } from "node-sass"
In my case VSCode added a arbitrary import from electron. After removing it my application worked.
import { Menu } from 'electron';
In my case, i needed to send a message from the node to react. I tried importing ipcRenderer from 'electron'; and const ipceRenderer = require('electron') This results in an error owing to webpack changing the node's require to its own webpack require. See more info here
I have a Node js server app which uses Express and Pug. I would like to bundle it to single script which can be deployed by pm2. There seem to be several problems with this.
In runtime I get Cannot find module "." and during compilation few messages like
WARNING in ./node_modules/express/lib/view.js 80:29-41 Critical
dependency: the request of a dependency is an expression
appear which come from dynamic imports like require(mod).__express. I assume Webpack can't statically resolve those and does not know which dependency to include.
How can this be solved ?
How do I make Pug compile and be part of the output js ?
It is because webpack rebundle node_modules (already bundled) dependencies and in the case of pug, it doesn't work.
You need to use webpack-node-externals within the webpack externals option in order to specifically ask not to re-bundle depedencies.
Install webpack-node-externals: npm i -D webpack-node-externals
Integrate it your webpack config file:
Example
// ...
const nodeExternals = require('webpack-node-externals')
module.exports = {
target: 'node',
entry: {
// ...
},
module: {
// ...
},
externals: [nodeExternals()],
output: {
// ...
},
}
I'm developing a ReactJS app with Babel and Webpack. I am using the create-react-app facebook script so it handles the Webpack´s configuration. My problem is that I created a js file and add:
var childProcess = require('child_process');
But when I want to compile the new version i get the following error :
Module not found: 'child_process'.
I don't know what to do with this . I have read that adding custom configurations to the webpack.config.js may be the solution but i am using create react app so I don't have the Webpack configuration. I tried running npm run eject and create my own webpack.config.js but it doesn't work.
I hope somebody could help me.
You need to configure the correct target inside the webpack configuration: https://webpack.github.io/docs/configuration.html#target
module.exports = {
entry: './path/to/my/entry/file.js',
...
target: 'node',// we can use node.js modules after adding this configuration
};