babelrc not sufficient to use with babel --watch - node.js

I have this .babelrc file:
{
"presets": ["env"],
"outDir":"target",
"include":[
"src/**/*.js"
],
"ignore": []
}
I run babel -w and I get this error message:
--watch requires --out-file or --out-dir. --watch requires filenames
do I need to specify more options at the command line or is there something I can add to my .babelrc file?

There is no way to configure this in your .babelrc. But you could add something like this to the scripts section of your package.json:
"scripts": {
"watch": "babel --watch src --out-dir dist"
}
Then you can just run npm run watch from the root of that project.
If you want to execute your project each time you compile, you can use babel-watch.

Related

Compile SCSS to CSS in Nest.js

How can I tell to Nest.JS to compile my SCSS files from assets into CSS format?
I have wrote this into nest-cli.json:
{
"collection": "#nestjs/schematics",
"sourceRoot": "src",
"compilerOptions": {
"assets": [
{
"include": "./assets/**.scss",
"outDir": "./assets/",
"watchAssets": true
}
]
}
}
But SCSS files are being copied without a conversion and I have no idea how to achive this.
Looks like Nest itself does not have the required tools, but you can compile SCSS to CSS with your script.
To do this you need to install node-sass and concurrently to run it with Nest together:
npm i --save-dev node-sass concurrently
Then go into package.json and modify scripts section: add tasks for SASS compilation and inject them into main build tasks:
scripts: {
// ...
// Add:
"css-once": "node_modules/node-sass/bin/node-sass src/css/style.scss assets/style.css",
"css-watch": "npm run css-once && node_modules/node-sass/bin/node-sass src/css/style.scss assets/style.css --watch",
// Modify:
"start": "npm run css-watch && nest start",
"start:dev": "concurrently --kill-others \"npm run css-watch\" \"nest start --watch\"",
"start:debug": "concurrently --kill-others \"npm run css-watch\" \"nest start --debug --watch\"",
"start:prod": "npm run css-once && node dist/main",
}
Note, that there are two different tasks for initial CSS compilation and for watching changes because node-sass in watch mode won't compile SCSS initially.

debugging webpack issue --config not found

so my webpack has been working fine. I needed a different structure then the default so I placed the webpack files in a build folder. As per documentation I placed the --config option in the package json but I am still not able to access the file in the debugger.
Below is my setup:
"scripts": {
"dev": "webpack-dev-server --inline --progress --config build/webpack.dev.conf.js",
"local": "webpack-dev-server --inline --progress --config build/webpack.local.conf.js",
"start": "npm run dev",
"build": "node build/build.js",
"build_dev": "node build/build.dev.js",
"build_stg": "node build/build.stg.js",
"build_prod": "node build/build.prod.js",
},
When I run the command node-nightly --inspect ./node_modules/webpack/bin/webpack.js
I get the error:
No configuration file found and no output filename configured via CLI option.
A configuration file could be named 'webpack.config.js' in the current directory.
In terms of my file structure I have under the root, a folder named build it contains the webpack config files (I was not sure how the structure is written on SO)
Version usage:
"webpack": "^3.12.0"
node 9.3
--config is a property on webpack. You are trying to set a --config property on webpack-dev-server webpack-dev-server
You can move your devserver to your webpack.config.js file
devServer: {
inline: true,
progress: true
}
and then refer to your webpack.config.js file directly in npm like so:
webpack --config ./build/yourfile.config.js
you can give any name you wish to the config file if you are using --config property else webpack will always try to find webpack.config.js in your projects root directory.
ELSE
you can create a webpack.config.js in your root and switch between config version on runtime like so:
//webpack.config.js
const TARGET = process.env.npm_lifecycle_event;
if (TARGET === 'build') {
module.exports = require('./buildScripts/webpack.config.dev');
}
else if (TARGET === 'build:prod') {
module.exports = require('./buildScripts/webpack.config.prod');
}
and in package.json you need the appropriate targets to match npm_lifecycle_event.
//package.json
"scripts": {
"build": "webpack --watch",
"build:prod": "webpack",
}

Use flag `--experimental-worker` with babel-node

babel-node --experimental-worker app.js
Using this command for starting my project in development mode. Output is:
error: unknown option--experimental-worker'
config .babelrc:
{ "presets": [ ["env", { "targets": { "node": "current" } }], "stage-0", "flow" ], "plugins": [ "transform-decorators-legacy", "transform-flow-strip-types" ] }
This flag is needed to use worker threads. Using babel 6.26
I just ran into this today and replied to the issue on GitHub here. I've pasted my fix below:
I was using Nodemon, and it turns out that there's an option to
include environment variables as NODE_OPTIONS in the nodemon.json
file. This did the trick for me:
{
"watch": ["server"],
"ext": "js",
"env": {
"NODE_OPTIONS": "--experimental-worker"
},
"exec": "babel-node server/server.js"
}
How to integrate Nodemon + worker_threads into a normal NodeJS app:
Set up Nodemon
Add a nodemon.json file to the root folder (example here)
Add this to nodemon.json:
"env": {
"NODE_OPTIONS": "--experimental-worker"
}
If you're setting up Nodemon for the first time, I found
this tutorial very helpful.
The idea is to split your command into two phases:
Phase 1:
babel app.js --out-file app-compiled.js
And phase 2:
node --experimental-worker app-compiled.js
In npm scripts you can then combine the two:
"scripts": {
"pre-build": "babel ./app.js --out-file ./app-compiled.js",
"serve": "yarn pre-build && node --experimental-worker ./app-compiled.js"
}
It not actually for me already. I am refused to use nodemon and run my code with command
node --experimental-worker -r babel-register $NODE_DEBUG_OPTION app.js
It`s help me use exeprimental workers with babel, but with nodemon - not

nodemon to exec "prestart" script at package.json

I want to setup nodemon to run the "prestart" script when server restarts, the reason, I'm using webpack and I want to build bundle.js every time a file changes, I'm not using webpack-dev-server cause I don't know how to set it up with an existing node app running, I got my backend on node.js, help on that will be appreciated.
The way I've been working is: run npm start every time I make a change on the code, but that too much effort.
Here's the scripts object at package.json so that you have an idea of what's going on:
"scripts": {
"bundle": "webpack --config webpack.config.js",
"prestart": "npm run bundle",
"start": "node server.js"
}
The way I've accomplished to do that is by creating a nodemon.json file with the exec property:
{
// ... Other conf (see an example in https://github.com/remy/nodemon/blob/master/doc/sample-nodemon.md)
"watch": [
"app" // Set your directories/files to watch
],
"exec": "npm run prestart && node server/index.js"
}

Webpack --watch and launching nodemon?

Thanks to an excellent answer by #McMath I now have webpack compiling both my client and my server. I'm now on to trying to make webpack --watch be useful. Ideally I'd like to have it spawn something like nodemon for my server process when that bundle changes, and some flavor of browsersync for when my client changes.
I realize it's a bundler/loader and not really a task runner, but is there some way to accomplish this? A lack of google results seems to indicate I'm trying something new, but this must have been done already..
I can always have webpack package to another directory and use gulp to watch it/copy it/browsersync-ify it, but that seems like a hack.. Is there a better way?
Install the following dependencies:
npm install npm-run-all webpack nodemon
Configure your package.json file to something as seen below:
package.json
{
...
"scripts": {
"start" : "npm-run-all --parallel watch:server watch:build",
"watch:build" : "webpack --watch",
"watch:server" : "nodemon \"./dist/index.js\" --watch \"./dist\""
},
...
}
After doing so, you can easily run your project by using npm start.
Don't forget config WatchIgnorePlugin for webpack to ignore ./dist folder.
Dependencies
npm-run-all - A CLI tool to run multiple npm-scripts in parallel or sequential.
webpack - webpack is a module bundler. Its main purpose is to bundle JavaScript files for usage in a browser, yet it is also capable of transforming, bundling, or packaging just about any resource or asset.
nodemon - Simple monitor script for use during development of a node.js app.
Faced the same problem and found the next solution - webpack-shell-plugin.
It
allows you to run any shell commands before or after webpack builds
So, thats my scripts in package.json:
"scripts": {
"clean": "rimraf build",
"prestart": "npm run clean",
"start": "webpack --config webpack.client.config.js",
"poststart": "webpack --watch --config webpack.server.config.js",
}
If I run 'start' script it launches next script sequence: clean -> start -> poststart.
And there is part of 'webpack.server.config.js':
var WebpackShellPlugin = require('webpack-shell-plugin');
...
if (process.env.NODE_ENV !== 'production') {
config.plugins.push(new WebpackShellPlugin({onBuildEnd: ['nodemon build/server.js --watch build']}));
}
...
"onBuildEnd" event fires only once after first build, rebuilds are not trigger "onBuildEnd", so nodemon works as intended
I like the simplicity of nodemon-webpack-plugin
webpack.config.js
const NodemonPlugin = require('nodemon-webpack-plugin')
module.exports = {
plugins: [new NodemonPlugin()]
}
then just run webpack with the watch flag
webpack --watch
In addition to #Ling's good answer:
If you want to build your project once, before you watch it with nodemon, you can use a webpack compiler hook. The plugin's code triggers nodemon in the done hook once after webpack has finished its compilation (see also this helpful post).
const { spawn } = require("child_process")
function OnFirstBuildDonePlugin() {
let isInitialBuild = true
return {
apply: compiler => {
compiler.hooks.done.tap("OnFirstBuildDonePlugin", compilation => {
if (isInitialBuild) {
isInitialBuild = false
spawn("nodemon dist/index.js --watch dist", {
stdio: "inherit",
shell: true
})
}
})
}
}
}
webpack.config.js:
module.exports = {
...
plugins: [
...
OnFirstBuildDonePlugin()
]
})
package.json:
"scripts": {
"dev" : "webpack --watch"
},
Hope, it helps.
There's no need to use plugins here. You could try running multiple nodemon instances like below. Try modifying the following script for your use case, and see if it works for you:
"scripts": {
"start": "nodemon --ignore './public/' ./bin/www & nodemon --ignore './public/' --exec 'yarn webpack'",
"webpack": "webpack --config frontend/webpack.config.js"
}
You don't need any plugins to use webpack and nodemon, just use this scripts on your package.json
"scripts": {
"start": "nodemon --ignore './client/dist' -e js,ejs,html,css --exec 'npm run watch'",
"watch": "npm run build && node ./server/index.js",
"build": "rimraf ./client/dist && webpack --bail --progress --profile"
},
#Ling has an answer very close to being correct. But it errors the first time somebody runs watch. You'll need to modify the solution as so to prevent errors.
Run npm install npm-run-all webpack nodemon
Create a file called watch-shim.js in your root. Add the following contents, which will create a dummy file and directory if they're missing.
var fs = require('fs');
if (!fs.existsSync('./dist')) {
fs.mkdir('./dist');
fs.writeFileSync('./dist/bundle.js', '');
}
Setup your scripts as so in package.json. This will only run watch if the watch-shim.js file runs successfully. Thereby preventing Nodemon from crashing due to missing files on the first run.
{
...
"scripts": {
"start": "npm run watch",
"watch": "node watch-shim.js && npm-run-all --parallel watch:server watch:build",
"watch:build": "webpack --progress --colors --watch",
"watch:server": "nodemon \"./dist/bundle.js\" --watch \"./dist/*\""
}
...
},
Assuming nodemon server.js touch the server.js file afterEmit:
// webpack.config.js
module.exports = {
// ...
plugins: [
// ...,
// 👇
apply: (compiler) => {
compiler.hooks.afterEmit.tap('AfterEmitPlugin', (compilation) => {
require('child_process').execSync('touch server.js') // $ touch server.js
});
}
]
}
I tried most of the solution provided above. I believe the best one is to use nodemon-webpack-plugin .
It is very simple to use i.e. just add
const NodemonPlugin = require('nodemon-webpack-plugin')
to webpack file with
new NodemonPlugin() as your plugin.
Below are the scripts to use it:
"scripts": {
"watch:webpack-build-dev": "webpack --watch --mode development",
"clean-db": "rm -rf ./db && mkdir -p ./db",
"local-dev": "npm run clean-db && npm run watch:webpack-build-dev"
...
}
After this you can simply run npm run local-dev.
Adding a module to development is usually not as bad as adding to a production one. And mostly you will be using it for the development anyway.
This also doesn't require any additional package like nodemon or npm-run-all etc.
Also nodemon-webpack-plugin only works in watch mode.

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