How to debug loopback 4 / node application with nodemon in visual studio code?
Looking for a solution that rebuilds the app when the loopback typescript code is changed. With option for debugging.
Regards,
Kelvijn
I finally found a solution to debug Loopback 4/node.js. If anyone has suggestions please do, this is the first solution that really does what I want.
Start Debugger by running:
npm run debug
With nodemon run the below command
nodemon --exec run debug
Add breakpoints by clicking on the left side of the line numbers in visual studio code.
Then in Visual Studio Code start application on debug mode by
Visual Studio Code (top-bar) -> Debug -> Start Debugging
package.json
"debug": "npm run build && node --nolazy --inspect-brk=9229 .",
"build": "lb-tsc es2017 --outDir dist"
launch.json
{
"version": "0.2.0",
"configurations": [
{
"type": "node",
"request": "attach",
"timeout": 1000000,
"name": "Attach",
"port": 9229,
"restart": true
}
]
}
tsconfig.json
Note: This file is by default extended by loopback, so you don't have to modify this.
{
"compilerOptions": {
"emitDecoratorMetadata": true,
"experimentalDecorators": true,
"target": "ES5",
"lib": ["es2015"],
"allowJs": true,
"skipLibCheck": true
},
"include": ["src"],
"exclude": ["node_modules", "platforms"]
}
Application structure
This is an alternative solution for nodemon.
tsc-watch is a similar tool that can be used with loopback 4. Basically, it works similar to the nodemon. To add tsc-watch as dev package,
run npm install tsc-watch --save-dev in your project location
add following lines to the package.json > scripts
"start": "node -r source-map-support/register .",
"dev": "tsc-watch -b --onSuccess \"npm start\""
now run npm run dev
For more details visit tsc-watch on npm or github
Create your own nodemon.json in root project source and put this in file
{
"ignore": [
"**/*.test.ts",
"**/*.spec.ts",
".git",
"node_modules"
],
"watch": [
"src"
],
"exec": "npm start",
"ext": "ts"
}
and run nodemon that's. Just make sure you installed nodemon in global scope.
Thanks for all the answers here I have manage to have something that works for my setup. I use yarn with loopback 4. Thanks to #dat-ho for the starting point.
First install nodemon in global scope
then add the nodemon config to package.json. I added this at the bottom of the file after devDependencies.
"nodemonConfig": {
"verbose": true,
"watch": [
"src/"
],
"ignore": [
"dist/*"
],
"ext": "ts",
"exec": "yarn run clean && yarn start"
}
The changes from previous answer was that nodemon detects the npm start script and it re runs npm start fine, but it does not rebuild and the changes were not shown in the running code. so I added the line "exec": "yarn run clean && yarn start" to clean and rerun the npm start command.
You can then add the following start:dev command to the package.json scripts section:
"start": "node -r source-map-support/register .",
"start:dev": "nodemon '--inspect'",
From there just run yarn start:dev and will rebuild when any typescript file changes. Hope this works for you guys. It took me a substantial amount of research to having this working. Hopefully the loopback guys can have something similar in future.
Related
I am using Loopback4 to develop api in Node.
I was using the instruction given to build and watch with nodemon
It worked, but it was getting slow, like about 15 seconds in my case.
I search for other other solution and came up with idea of using Turborepo and the nodemon solution.
I wanted to know if there are better solutions or any issues with it
Gist of the solution
run build in watch mode and restart the dev server if js files in dist folder change
use Turbo repo to run these build and restart server tasks
Steps
Setup build and watch with nodemon as described in the thread
you should have something like this in the script
"scripts": {
"dev:server:watch": "nodemon server.js"
}
// watch src folder
// ignore dist
// ext only ts files
// npm start to start the dev server on any changes to the files
"nodemonConfig": {
"verbose": true,
"watch": [
"src/"
],
"ignore": [
"dist/*"
],
"ext": "ts",
"exec": "npm start"
}
Install turbo build system
yarn add turbo --dev
Update nodemon config to restart server on changes in js files in dist folder after build step
"nodemonConfig": {
"verbose": true,
"watch": [
"./dist/"
],
"ext": "js",
"exec": "yarn run start"
},
Add turbo.json
{
"pipeline": {
"dev": {
"dependsOn": ["build:watch", "dev:server:watch"]
},
"build:watch": {
"outputs": [
".dist/**"
]
},
"lint": {
"outputs": []
}
}
}
Add dev script in package.json "scripts"
"dev": "turbo run dev",
Run
yarn run dev
This seems to have reduced the build times to about 3 seconds
Can anyone confirm if this is an acceptable solution, points out any issues
Thanks
In my package.json I have some scripts defined that look like this:
"scripts": {
"build": "tsc -p tsconfig.json",
"run": "node --experimental-specifier-resolution=node .",
"start": "npm run build && npm run run"
}
For now I just used npm run start from the terminal to compile and run everything but I want to use breakpoints now and would like to switch to the VSCode debugging.
I don't know what the launch.json configuration should look like to run scripts.
My project structure looks something like this:
.
├── package.json
├── src/
│ └── start.ts
└── dist/
└── start.js
What I think my best attempt so far was:
{
"name": "Launch via NPM",
"request": "launch",
"type": "node",
"cwd": "${workspaceRoot}",
"runtimeExecutable": "npm",
"runtimeArgs": [
"run",
"start"
],
},
Which sadly gives me the following error:
Exception has occurred: Error: ENOENT: no such file or directory, stat '{cwd}\git.COM'
Replacing "runtimeArgs": ["run","start"], with "command": "npm run start", gives me the same error.
Using a NPM script
You could create an additional script in your package.json to launch node with the instruction to wait for a debugger to be attached. IMHO, this is not ideal and I would avoid it but it's sometimes necessary (for example when node is launched by some shell script):
"scripts": {
"debug": "npm run build && node --experimental-specifier-resolution=node --inspect-brk ."
}
Then you would need a configuration in your launch.json to attach the debugger to the waiting node process:
{
"name": "Attach",
"type": "node",
"request": "attach",
"skipFiles": ["<node_internals>/**"],
"outFiles": ["${workspaceFolder}/dist/**/*.js"]
}
Launching node directly
Another possibility is to launch node in your launch.json with the appropriate arguments. There is a little code duplication with your package.json but that's how I do it myself.
Note that if you want to debug directly your TS files, you have to generate the source maps and indicate the location of the generated JS files.
Here is how it would look like:
{
"name": "Debug",
"type": "node",
"request": "launch",
"skipFiles": ["<node_internals>/**"],
"program": "${workspaceFolder}/src/start.ts",
"outFiles": ["${workspaceFolder}/dist/**/*.js"],
"runtimeArgs": [
"--experimental-specifier-resolution=node"
]
}
To ensure your TS code is built, I would run TSC in watch mode in another terminal window:
tsc -p tsconfig.json --watch
Is there a way to debug a nestJS project with nodemon.
i tried this code in launch.json
{
"type": "node",
"request": "launch",
"name": "NestJs Watch",
"runtimeExecutable": "npm",
"runtimeArgs": ["run-script", "start:dev"],
"cwd": "${workspaceFolder}",
"port": 3000
}
but i got this error
and my nodemon.json file
{
"watch": ["src"],
"ext": "ts",
"ignore": ["src/**/*.spec.ts"],
"exec": "ts-node -r --inspect=3000 tsconfig-paths/register src/main.ts"
}
If we want to work in the debug mode, with a better chance to see what is happening in the code, we need to use "nodemon" with dedicated a "nodemon.json" configuration file to run our development "nestjs" server with the ts-node module hooking up the typescript compiler.
The steps that worked for me are:
Install nodemon and ts-node:
npm i --save-dev nodemon ts-node
Next, add a nodemon.json file with debug and ts-node support in the root of your project:
file: (project root) nodemon.json
and insert this config. JSON text:
{
"watch": ["src"],
"ext": "ts",
"ignore": ["src/**/*.spec.ts"],
"exec": "node --inspect-brk -r ts-node/register src/main.ts"
}
Next adjust file: package.json - section: "start:debug"
file: (project root) package.json
The original value typically is:
...
> "start:debug": "nest start --debug --watch",
...
Change it to:
...
> "start:debug": "nodemon --config nodemon.json"
...
Now, in VSC (Visual Studio Code) make sure that you can see on the very bottom status bar:
"Auto Attach: On"
if not, on your keyboar press the keys:
Ctrl + Shift + p
to open the Command Palette, and paste in this command:
Debug: Toggle auto attach
and press Enter.
Now you should see the:
"Auto Attach: On"
Now debugging with break points should work.
Start with placing a break point in the beginning of your program code
(to make sure the flow does not end before your breakpoint ...)
file: (project root) 'main.ts'
> function: bootstrap() {
console.log('test'); // -- place break point here
// ... other code ...
}
In VSC (Visula Studio Code) select menu item:
Start debugging (or F5)
and select Node.js as the Environment option in the popup menu.
The breakpoint should be caught now in the bootstrap() function.
I run this command:
npm run start:dev
Try this nodemon config:
{
"watch": ["src"],
"ext": "ts",
"ignore": ["src/**/*.spec.ts"],
"exec": "node --inspect-brk -r tsconfig-paths/register -r ts-node/register src/main.ts"
}
and then you can run: nodemon --config nodemon.json
I'm having trying to debug my app on Visual Studio Code. I have the following config on my package.json:
"scripts": {
"build": "rimraf dist/ && babel ./ --out-dir dist/ --ignore ./node_modules,./.babelrc,./package.json,./npm-debug.log --copy-files",
"start": "npm run build && node --inspect=12345 dist/app.js"
}
Im using ES6 on my Node app, that's why it is kinda messy my build config.
When I run npm start everything works fine, I can use my app.
Now to try to debug it, I have set the following launch configurations:
"configurations": [
{
"type": "node",
"name": "Attach to Remote",
"request": "attach",
"port": 12345
},
{
"type": "node",
"request": "launch",
"name": "Launch Program",
"program": "${workspaceFolder}\\dist\\app.js"
}
]
Both of them ""work"": VS Code switch to "debug mode" but I can't hit any breakpoints. They all get grayed out:
I have tried to fix using this answer, but couldn't get it to work...
Any help?
Thanks in advance!
I am using VS Code v 1.28.2 and I'm able to debug both ways.
1) With the built in debuger ( Menu -> Debug -> Start Debuging)
2) starting the application with node inspect index.js. In that case you have to declare breakpoints in your code with the debugger; keyword. Then, when in debug-mode and stoped in a breakpoint, you continue execution typing cont in the command line.
hope it helps
I found out I was just missing the --source-maps from my babel-cli command... -.-
After adding it, VSCode is able to find the breakpoints.
So basically the solution was:
Add --source-maps to my build command:
"scripts": {
"build": "rimraf dist/ && babel ./ --out-dir dist/ --ignore ./node_modules,./.babelrc,./package.json,./npm-debug.log --copy-files --source-maps",
"start": "npm run build && node --inspect=12345 dist/app.js"
}
And I configured a launch as follows:
"configurations": [
{
"type": "node",
"request": "launch",
"name": "Launch Program",
"program": "${workspaceFolder}\\dist\\app.js",
"preLaunchTask": "npm: build"
}
]
Hope it helps someone!
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