Develop Reference

Electron Dialog filePath "\\" to "/"?

I open an dialog in electron to select an folder and I want to read out the file path.
But the result.filePaths gives me an filePath with \\ what is not workible for me, to read later the files in the folder. 😅
Result now:
"P:\\Social Media\\Soundboard\\Sounds"
Expected Result:
"P:/Social Media/Soundboard/Sounds"
Is it any way to convert it to "/"? 🤔
My code:
const dialog = require('electron').remote.dialog
dialog.showOpenDialog({
properties: ['openDirectory', 'multiSelections']
}).then(result => {
//Get Selected Folders
folderpath = result.filePaths
console.log(folderpath)
});

Windows uses \ to separate nested resources instead of /. But it supports both. If you still want to convert \\ to /. You can try the below method.
//Get Selected Folders
folderpath = result.filePaths.replaceAll('\\', '/');
console.log(folderpath);

Here's how I develop electron apps to work on both unix and windows without any issues.
Instead of using the path module function, I extended the functionality by using the module below and call that instead. This will sanitize all paths and convert them to correct unix paths like '/var/path/file' or 'C:/path/file'.
Windows can actually work with unix paths for creating/reading/updating/moving files and folders.
export default {
extname (file) {
return path.extname(file)
},
resolve () {
return this.sanitizePath(Array.from(arguments).join('/').replace('//', '/'))
},
normalize () {
const file = this.resolve(...arguments)
return this.sanitizePath(path.normalize(file))
},
basename (file, ext = '') {
return this.sanitizePath(path.basename(file, ext))
},
dirname (file) {
return this.sanitizePath(path.dirname(file))
},
relative (from, to) {
return this.sanitizePath(path.relative(path.resolve(from), path.resolve(to)))
},
sanitizePath (absPath) {
// fix windows separator
return absPath.replaceAll(path.sep, '/')
}
}
The only time I needed windows specific paths was with shell.moveItemToTrash(file) and for that I had to us this client side function
convertPathForWin (file, os = navigator.platform) {
return (os.toLowerCase() === 'win32') ? file.replaceAll('/', '\\') : file
}

How to delete multiple PDF files in the current directory in javascript/node.js

I wanted to delete multiple files which are ending with .pdf under the current directory. Suppose I have 3 different pdf files, 1 image file, and one text file, so in these, I want to delete those 3 different pdf files only.
What I have tried.
1st method
fs.unlinkSync('./'+*+pdfname); -> I know this does not make sense
2nd method
try {
var files = (here the list of files should come. However i am failing to get those);
var path="./"
files.forEach(path => fs.existsSync(path) && fs.unlinkSync(path))
} catch (err) {
console.error("not exist")
}
Any different approaches would be appreciated.
Update for the solution:
I have got the solution for my requirement, I just wanted my function to delete all the pdf files and function to be synchronous. However 99% of the solution given by the below author -> https://stackoverflow.com/a/66558251/11781464
fs.readdir is asynchronous and just needs to make it synchronous fs.readdirSync.
below is the updated code and all the credit should go to the author https://stackoverflow.com/a/66558251/11781464.
Updated code
try {
const path = './'
// Read the directory given in `path`
fs.readdirSync(path).forEach((file) => {
// Check if the file is with a PDF extension, remove it
if (file.split('.').pop().toLowerCase() === 'pdf') {
console.log(`Deleting file: ${file}`);
fs.unlinkSync(path + file)
}
});
console.log("Deleted all the pdf files")
return true;
} catch (err) {
console.error("Error in deleting files",err);
}

You can read the directory using fs.readdir and then check for PDF files and delete them. Like this:
fs = require('fs');
try {
path = './'
// Read the directory given in `path`
const files = fs.readdir(path, (err, files) => {
if (err)
throw err;
files.forEach((file) => {
// Check if the file is with a PDF extension, remove it
if (file.split('.').pop().toLowerCase() == 'pdf') {
console.log(`Deleting file: ${file}`);
fs.unlinkSync(path + file)
}
});
});
} catch (err) {
console.error(err);
}

Preliminary Reading
The current working directory of the Node.js process - see update below answer
Path methods
resolve
extName
File System methods
fs.readdirSync
fs.unlinkSync
and classes
dirent
Example
"use strict";
const fs = require('fs');
const path = require('path');
const cwd = process.cwd();
fs.readdirSync( cwd, {withFileTypes: true})
.forEach( dirent => {
if(dirent.isFile()) {
const fileName = dirent.name;
if( path.extname(fileName).toLowerCase() === ".pdf") {
fs.unlinkSync( path.resolve( cwd, fileName));
}
}
});
Notes
untested code
If unlinkSync fails I would assume it returns -1 as per the unlink(2) man page linked in documentation. Personally I would test this using a filename that doesn't exist in cwd.
I believe the {withFileTypes: true} option for readdirSync returns dirent objects with a mime-type value that would allow you to check for files of type application/pdf regardless of extension (not attempted in the example).
Update: path(resolve) adds the current working directory at the beginning of the returned path, when necessary, by default. path.resolve(fileName) will work equally as well as path.resolve(cwd, fileName) in the example.

It seems you know how to delete (unlink) the files - you are asking how to get the file paths?
Try using glob:
const pdfFiles = require("glob").globSync("*.pdf");

Hi here i am attaching tested code for delete all ( only ) .pdf files and not other extension files like .txt , .docs etc from directory.
Note : You can delete any files or directory only from server side.
const fs = require('fs');
const path = require('path')
fs.readdir('../path to directory', (err, files) => {
const pdfFiles = files.filter(el => path.extname(el) === '.pdf')
pdfFiles.forEach(file => {
console.log("Removing File -> ",file);
var filename = "../path to directory/"+file;
fs.unlink(filename,function(err){
if(err) return console.log(err);
console.log('file deleted successfully');
});
});
});
This will gives you a following result in console log.
Removing File -> note.pdf
Removing File -> note2.pdf
file deleted successfully
file deleted successfully
Please feel free to comment any query if have..

Listen for hot update events on the client side with webpack-dev-derver?

This is a bit of an edge case but it would be helpful to know.
When developing an extension using webpack-dev-server to keep the extension code up to date, it would be useful to listen to "webpackHotUpdate"
Chrome extensions with content scripts often have two sides to the equation:
Background
Injected Content Script
When using webpack-dev-server with HMR the background page stays in sync just fine. However content scripts require a reload of the extension in order to reflect the changes. I can remedy this by listening to the "webpackHotUpdate" event from the hotEmmiter and then requesting a reload. At present I have this working in a terrible and very unreliably hacky way.
var hotEmitter = __webpack_require__(XX)
hotEmitter.on('webpackHotUpdate', function() {
console.log('Reloading Extension')
chrome.runtime.reload()
})
XX simply represents the number that is currently assigned to the emitter. As you can imagine this changed whenever the build changes so it's a very temporary proof of concept sort of thing.
I suppose I could set up my own socket but that seems like overkill, given the events are already being transferred and I simply want to listen.
I am just recently getting more familiar with the webpack ecosystem so any guidance is much appreciated.

Okay!
I worked this out by looking around here:
https://github.com/facebookincubator/create-react-app/blob/master/packages/react-dev-utils/webpackHotDevClient.js
Many thanks to the create-react-app team for their judicious use of comments.
I created a slimmed down version of this specifically for handling the reload condition for extension development.
var SockJS = require('sockjs-client')
var url = require('url')
// Connect to WebpackDevServer via a socket.
var connection = new SockJS(
url.format({
// Default values - Updated to your own
protocol: 'http',
hostname: 'localhost',
port: '3000',
// Hardcoded in WebpackDevServer
pathname: '/sockjs-node',
})
)
var isFirstCompilation = true
var mostRecentCompilationHash = null
connection.onmessage = function(e) {
var message = JSON.parse(e.data)
switch (message.type) {
case 'hash':
handleAvailableHash(message.data)
break
case 'still-ok':
case 'ok':
case 'content-changed':
handleSuccess()
break
default:
// Do nothing.
}
}
// Is there a newer version of this code available?
function isUpdateAvailable() {
/* globals __webpack_hash__ */
// __webpack_hash__ is the hash of the current compilation.
// It's a global variable injected by Webpack.
return mostRecentCompilationHash !== __webpack_hash__
}
function handleAvailableHash(data){
mostRecentCompilationHash = data
}
function handleSuccess() {
var isHotUpdate = !isFirstCompilation
isFirstCompilation = false
if (isHotUpdate) { handleUpdates() }
}
function handleUpdates() {
if (!isUpdateAvailable()) return
console.log('%c Reloading Extension', 'color: #FF00FF')
chrome.runtime.reload()
}
When you are ready to use it (during development only) you can simply add it to your background.js entry point
module.exports = {
entry: {
background: [
path.resolve(__dirname, 'reloader.js'),
path.resolve(__dirname, 'background.js')
]
}
}
For actually hooking into the event emitter as was originally asked you can just require it from webpack/hot/emitter since that file exports an instance of the EventEmitter that's used.
if(module.hot) {
var lastHash
var upToDate = function upToDate() {
return lastHash.indexOf(__webpack_hash__) >= 0
}
var clientEmitter = require('webpack/hot/emitter')
clientEmitter.on('webpackHotUpdate', function(currentHash) {
lastHash = currentHash
if(upToDate()) return
console.log('%c Reloading Extension', 'color: #FF00FF')
chrome.runtime.reload()
})
}
This is just a stripped down version straight from the source:
https://github.com/webpack/webpack/blob/master/hot/dev-server.js

I've fine-tuned the core logic of the crx-hotreload package and come up with a build-tool agnostic solution (meaning it will work with Webpack but also with anything else).
It asks the extension for its directory (via chrome.runtime.getPackageDirectoryEntry) and then watches that directory for file changes. Once a file is added/removed/changed inside that directory, it calls chrome.runtime.reload().
If you'd need to also reload the active tab (when developing a content script), then you should run a tabs.query, get the first (active) tab from the results and call reload on it as well.
The whole logic is ~35 lines of code:
/* global chrome */
const filesInDirectory = dir => new Promise(resolve =>
dir.createReader().readEntries(entries =>
Promise.all(entries.filter(e => e.name[0] !== '.').map(e =>
e.isDirectory
? filesInDirectory(e)
: new Promise(resolve => e.file(resolve))
))
.then(files => [].concat(...files))
.then(resolve)
)
)
const timestampForFilesInDirectory = dir => filesInDirectory(dir)
.then(files => files.map(f => f.name + f.lastModifiedDate).join())
const watchChanges = (dir, lastTimestamp) => {
timestampForFilesInDirectory(dir).then(timestamp => {
if (!lastTimestamp || (lastTimestamp === timestamp)) {
setTimeout(() => watchChanges(dir, timestamp), 1000)
} else {
console.log('%c 🚀 Reloading Extension', 'color: #FF00FF')
chrome.runtime.reload()
}
})
}
// Init if in dev environment
chrome.management.getSelf(self => {
if (self.installType === 'development' &&
'getPackageDirectoryEntry' in chrome.runtime
) {
console.log('%c 📦 Watching for file changes', 'color: #FF00FF')
chrome.runtime.getPackageDirectoryEntry(dir => watchChanges(dir))
}
})
You should add this script to your manifest.json file's background scripts entry:
"background": ["reloader.js", "background.js"]
And a Gist with a light explanation in the Readme: https://gist.github.com/andreasvirkus/c9f91ddb201fc78042bf7d814af47121

Work around to unsolved npm link symlink requires?

When developing an NPM package, it's common to use:
npm link
It allows to modify <myPackage> under development without the need of publishing and unpublishing all the time! The developer can make any changes locally and see it immediately.
It's installed into a project by using:
npm link <myPackage>
It's great, but there's a problem if the <myPackage> have a require(path).
It'll use the real location of <myPackage> as __dirname, for example, instead of the expected location of the symlink, that should be local to the project, like a regular node_module.
The solution I found so far, for my particular case works fine:
module.exports = {
loadImage: function (filename) {
var img
if (typeof window !== 'undefined' && ({}).toString.call(window) === '[object Window]') {
try {
img = require('../../src/images/' + filename)
} catch (e) {
// Development only
img = require('./template/src/images/' + filename)
}
} else {
img = '/assets/images/' + filename
}
return img
}
}
But as you can imagine, this cause Warning messages in the Browser.
While I'm aware of the reason why of this problem, ideally, I'd like to suppress the error.

I believe it won't be a very popular question, in that case, here's a nice option that won't cause any warning messages and that is quite specific to the NPM Package development stage.
The following modules.exports expose some code snippets you'd like to import into your application. You'll find the loadImage method, with a fallback for the require(path):
module.exports = {
loadImage: function (filename) {
if (typeof window !== 'undefined' && ({}).toString.call(window) === '[object Window]') {
return (process.env.NPM_PACKAGE_DEV && require('./template/src/images/' + filename) ||
require('./template/src/images/' + filename))
} else {
return '/assets/images/' + filename
}
},
isBrowser: function () {
return (typeof window !== 'undefined' && ({}).toString.call(window) === '[object Window]')
}
}
What's good about this, is that you can set the NPM_PACKAGE_DEV by running the command, than initialize the node server (osx terminal syntax):
export NPM_PACKAGE_DEV=1 && node server.js
If the NPM_PACKAGE_DEV is omitted, the require() fallback to the end use path, that is relative to the project node_modules directory.
Hope this helps someone else in the future!

How do I require() from the console using webpack?

How do I require() / import modules from the console? For example, say I've installed the ImmutableJS npm, I'd like to be able to use functions from the module while I'm working in the console.

Here's another more generic way of doing this.
Requiring a module by ID
The current version of WebPack exposes webpackJsonp(...), which can be used to require a module by ID:
function _requireById(id) {
return webpackJsonp([], null, [id]);
}
or in TypeScript
window['_requireById'] =
(id: number): any => window['webpackJsonp'];([], null, [id]);
The ID is visible at the top of the module in the bundled file or in the footer of the original source file served via source maps.
Requiring a module by name
Requiring a module by name is much trickier, as WebPack doesn't appear to keep any reference to the module path once it has processed all the sources. But the following code seems to do the trick in lot of the cases:
/**
* Returns a promise that resolves to the result of a case-sensitive search
* for a module or one of its exports. `makeGlobal` can be set to true
* or to the name of the window property it should be saved as.
* Example usage:
* _requireByName('jQuery', '$');
* _requireByName('Observable', true)´;
*/
window['_requireByName'] =
(name: string, makeGlobal?: (string|boolean)): Promise<any> =>
getAllModules()
.then((modules) => {
let returnMember;
let module = _.find<any, any>(modules, (module) => {
if (_.isObject(module.exports) && name in module.exports) {
returnMember = true;
return true;
} else if (_.isFunction(module.exports) &&
module.exports.name === name) {
return true;
}
});
if (module) {
module = returnMember ? module.exports[name] : module.exports;
if (makeGlobal) {
const moduleName = makeGlobal === true ? name : makeGlobal as string;
window[moduleName] = module;
console.log(`Module or module export saved as 'window.${moduleName}':`,
module);
} else {
console.log(`Module or module export 'name' found:`, module);
}
return module;
}
console.warn(`Module or module export '${name}'' could not be found`);
return null;
});
// Returns promise that resolves to all installed modules
function getAllModules() {
return new Promise((resolve) => {
const id = _.uniqueId('fakeModule_');
window['webpackJsonp'](
[],
{[id]: function(module, exports, __webpack_require__) {
resolve(__webpack_require__.c);
}},
[id]
);
});
}
This is quick first shot at this, so it's all up for improvement!

Including this in a module will allow require([modules], function) to be used from a browser
window['require'] = function(modules, callback) {
var modulesToRequire = modules.forEach(function(module) {
switch(module) {
case 'immutable': return require('immutable');
case 'jquery': return require('jquery');
}
})
callback.apply(this, modulesToRequire);
}
Example Usage:
require(['jquery', 'immutable'], function($, immutable) {
// immutable and $ are defined here
});
Note: Each switch-statement option should either be something this module already requires, or provided by ProvidePlugin
Sources:
Based on this answer, which can be used to add an entire folder.
Alternative method from Webpack Docs - which allows something like require.yourModule.function()

I found a way that works, for both WebPack 1 and 2. (as long as the source is non-minified)
Repo: https://github.com/Venryx/webpack-runtime-require
Install
npm install --save webpack-runtime-require
Usage
First, require the module at least once.
import "webpack-runtime-require";
It will then add a Require() function to the window object, for use in the console, or anywhere in your code.
Then just use it, like so:
let React = Require("react");
console.log("Retrieved React.Component: " + React.Component);
It's not very pretty (it uses regexes to search the module wrapper functions) or fast (takes ~50ms the first call, and ~0ms after), but both of these are perfectly fine if it's just for hack-testing in the console.
Technique
The below is a trimmed version of the source to show how it works. (see the repo for the full/latest)
var WebpackData;
webpackJsonp([],
{123456: function(module, exports, __webpack_require__) {
WebpackData = __webpack_require__;
}},
[123456]
);
var allModulesText;
var moduleIDs = {};
function GetIDForModule(name) {
if (allModulesText == null) {
let moduleWrapperFuncs = Object.keys(WebpackData.m).map(moduleID=>WebpackData.m[moduleID]);
allModulesText = moduleWrapperFuncs.map(a=>a.toString()).join("\n\n\n");
// these are examples of before and after webpack's transformation: (which the regex below finds the var-name of)
// require("react-redux-firebase") => var _reactReduxFirebase = __webpack_require__(100);
// require("./Source/MyComponent") => var _MyComponent = __webpack_require__(200);
let regex = /var ([a-zA-Z_]+) = __webpack_require__\(([0-9]+)\)/g;
let matches = [];
let match;
while (match = regex.exec(allModulesText))
matches.push(match);
for (let [_, varName, id] of matches) {
// these are examples of before and after the below regex's transformation:
// _reactReduxFirebase => react-redux-firebase
// _MyComponent => my-component
// _MyComponent_New => my-component-new
// _JSONHelper => json-helper
let moduleName = varName
.replace(/^_/g, "") // remove starting "_"
.replace(new RegExp( // convert chars where:
"([^_])" // is preceded by a non-underscore char
+ "[A-Z]" // is a capital-letter
+ "([^A-Z_])", // is followed by a non-capital-letter, non-underscore char
"g"),
str=>str[0] + "-" + str[1] + str[2] // to: "-" + char
)
.replace(/_/g, "-") // convert all "_" to "-"
.toLowerCase(); // convert all letters to lowercase
moduleIDs[moduleName] = parseInt(id);
}
}
return moduleIDs[name];
}
function Require(name) {
let id = GetIDForModule(name);
return WebpackData.c[id].exports;
}

Being able to use require modules in the console is handy for debugging and code analysis. #psimyn's answer is very specific so you aren't likely to maintain that function with all the modules you might need.
When I need one of my own modules for this purpose, I assign a window property to it so I can get at it e.g window.mymodule = whatever_im_exporting;. I use the same trick to expose a system module if I want to play with it e.g:
myservice.js:
let $ = require('jquery');
let myService = {};
// local functions service props etc...
module.exports = myService;
// todo: remove these window prop assignments when done playing in console
window.$ = $;
window.myService = myService;
It is still a bit of a pain, but digging into the bundles, I can't see any way to conveniently map over modules.

The answer from #Rene Hamburger is good but unfortunately doesn't work anymore (at least with my webpack version). So I updated it:
function getWebpackInternals() {
return new Promise((resolve) => {
const id = 'fakeId' + Math.random();
window['webpackJsonp'].push(["web", {
[id]: function(module, __webpack_exports__, __webpack_require__) {
resolve([module, __webpack_exports__, __webpack_require__])
}
},[[id]]]);
});
}
function getModuleByExportName(moduleName) {
return getWebpackInternals().then(([_, __webpack_exports__, __webpack_require__]) => {
const modules = __webpack_require__.c;
const moduleFound = Object.values(modules).find(module => {
if (module && module.exports && module.exports[moduleName]) return true;
});
if (!moduleFound) {
console.log('couldnt find module ' + moduleName);
return;
}
return moduleFound.exports[moduleName];
})
}
getModuleByExportName('ExportedClassOfModule');

expose-loader is, in my opinion, a more elegant solution:
require("expose-loader?libraryName!./file.js");
// Exposes the exports for file.js to the global context on property "libraryName".
// In web browsers, window.libraryName is then available.

Adding the below code to one of your modules will allow you to load modules by id.
window.require = __webpack_require__;
In the console use the following:
require(34)

You could do something similar as psimyn advised by
adding following code to some module in bundle:
require.ensure([], function () {
window.require = function (module) {
return require(module);
};
});
Use require from console:
require("./app").doSomething();
See more

After making an npm module for this (see my other answer), I did a search on npms.io and seem to have found an existing webpack-plugin available for this purpose.
Repo: https://www.npmjs.com/package/webpack-expose-require-plugin
Install
npm install --save webpack-expose-require-plugin
Usage
Add the plugin to your webpack config, then use at runtime like so:
let MyComponent = require.main("./path/to/MyComponent");
console.log("Retrieved MyComponent: " + MyComponent);
See package/repo readme page for more info.
EDIT
I tried the plugin out in my own project, but couldn't get it to work; I kept getting the error: Cannot read property 'resource' of undefined. I'll leave it here in case it works for other people, though. (I'm currently using the solution mentioned above instead)

After both making my own npm package for this (see here), as well as finding an existing one (see here), I also found a way to do it in one-line just using the built-in webpack functions.
It uses WebPack "contexts": https://webpack.github.io/docs/context.html
Just add the following line to a file directly in your "Source" folder:
window.Require = require.context("./", true, /\.js$/);
Now you can use it (eg. in the console) like so:
let MyComponent = Require("./Path/To/MyComponent");
console.log("Retrieved MyComponent: " + MyComponent);
However, one important drawback of this approach, as compared to the two solutions mentioned above, is that it seems to not work for files in the node_modules folder. When the path is adjusted to "../", webpack fails to compile -- at least in my project. (perhaps because the node_modules folder is just so massive)