How nestjs configures path aliases in a project - nestjs

Question

I configured the path alias in tsconfig.json of the nestjs project, but there was an error while running.
I tried to configure like Angular, but there was an error in nestjs
This is my tsconfig.json
{
"compilerOptions": {
"module": "commonjs",
"declaration": true,
"removeComments": true,
"emitDecoratorMetadata": true,
"experimentalDecorators": true,
"target": "es6",
"sourceMap": true,
"outDir": "./dist",
"baseUrl": "./",
"incremental": true,
"paths": {
"~auth/*": ["src/auth/*"]
}
},
"exclude": ["node_modules"]
}
Use it like this
import { userLoginJwt } from '~auth/jwt-names'
Startup error
$ npm run start:dev
[0] internal/modules/cjs/loader.js:584
[0] throw err;
[0] ^
[0]
[0] Error: Cannot find module 'src/auth/jwt-names'
Sorry, I emphasize here that running npm run start works fine, but running npm run start:dev can lead to unexpected situations.

Answer 1

This job, I work：
Modify my 'tsconfig.json'
{
"compilerOptions": {
"module": "commonjs",
"declaration": true,
"removeComments": true,
"emitDecoratorMetadata": true,
"experimentalDecorators": true,
"target": "es6",
"sourceMap": true,
"outDir": "./dist",
"baseUrl": "./src",
"incremental": true,
"paths": {
"~auth/*": ["auth/*"]
}
},
"exclude": ["node_modules"]
}
Add 'tsconfig-paths-bootstrap.js' file
// tsconfig-paths-bootstrap.js
const tsConfig = require('./tsconfig.json');
const tsConfigPaths = require('tsconfig-paths');
tsConfigPaths.register({
baseUrl: tsConfig.compilerOptions.outDir,
paths: tsConfig.compilerOptions.paths,
});
Modify the 'nodemon.json' file
{
"watch": ["dist"],
"ext": "js",
"exec": "node -r ./tsconfig-paths-bootstrap.js dist/main.js"
}
Use path alias
import { userLoginJwt } from '~auth/jwt-names';
Now executing the npm run start:dev error has disappeared.

Answer 2

src is not an available folder after compilation, as all the code is moved to the dist folder. Rather, what you should do in your tsconfig is set up a baseUrl to point to src and the outDir to point to dist then remove src from your paths. I'd also suggest reading up on Typescript path mapping to get a better understanding of what is happening.

Answer 3

TL;DR;
Update your package.json
"start:dev": "nest start --watch --exec 'node -r tsconfig-paths/register -r ts-node/register ./src/main.ts'"
Use npm run start:dev

Answer 4

Only needs:
"moduleResolution": "node",
"baseUrl": "src",
"paths": {
"#lib/*": ["lib/*"],
"#models/*": ["models/*"],
"#plugins/*": ["plugins/*"],
"#routes/*": ["routes/*"],
"#services/*": ["services/*"],
"#api": ["api/index"]
}
https://medium.com/zero-equals-false/how-to-use-module-path-aliases-in-visual-studio-typescript-and-javascript-e7851df8eeaa

Answer 5

How nestjs configures path aliases in a project
It doesn't you are showing us the tsconfig file - its TS that is declaring the paths
"paths": {
"~auth/*": ["src/auth/*"]
}
would be better if it followed what appears to be a convention of adding # instead of tilda
"paths": {
"#auth/*": ["src/auth/*"]
}
Or just all
"paths": {
"*": [
"./*"
]
},
So thats the path reference sorted... now onto tsconfig-paths for using short paths after compilation. So the above will be good for the TS, but after its been transpiled to JS the paths are no longer referenced as its JS now... which is why it fails with the start command.
You will need to create a bootstrap script like shown in the docs and calling that in your package.json just before the build command.