TypeScript path aliases in tsconfig.json not found

Question

The user defined paths in tsconfig.json are not found – TypesScript says … I have reinitialized the whole project. Used stock ts configs, checked every setting, updated everything. It just don't want to work.

Project structure:

|-./
|--index.ts
|--package.json
|--tsconfig.json
|--database/
|---dbOperations/
|----index.ts
|--api/
|---server.ts

package.json:

{
  "name": "name",
  "version": "0.1.0",
  "private": true,
  "description": "desc.",
  "main": "index.ts ",
  "scripts": {
    "test": "jest --config jest.config.json",
    "tsnode": "ts-node index.ts",
    "lint": "eslint '**/*.ts' --ignore-pattern node_modules/",
  },
  "license": "ISC",
  "devDependencies": {
    "@babel/core": "^7.15.0",
    "@babel/preset-env": "^7.15.0",
    "@babel/preset-typescript": "^7.15.0",
    "@types/cors": "^2.8.12",
    "@types/express": "^4.17.13",
    "@types/jest": "^27.0.1",
    "@typescript-eslint/eslint-plugin": "^4.32.0",
    "@typescript-eslint/parser": "^4.32.0",
    "eslint": "^7.32.0",
    "jest": "^27.1.0",
    "nodemon": "^2.0.12",
    "ts-jest": "^27.0.5",
    "ts-node": "^10.1.0",
    "typescript": "^4.3.5"
  },
  "dependencies": {
    "express": "^4.17.1",
  }
}

tsconfig.json (initial config after tsc --init with paths):

{
  "compilerOptions": {
    "strict": true,
    "target": "es5",
    "module": "commonjs",
    "esModuleInterop": true,
    "skipLibCheck": true,
    "forceConsistentCasingInFileNames": true,
    "baseUrl": ".",
    "paths": {
      "@app/*": [
        "./*"
      ],
      "@api/*": [
        "api/*"
      ],
      "@database/*": [
        "database/*"
      ],
      "@dbOperations": [
        "database/dbOperations/index.ts"
      ]
    },
  }
}

When I do import {x, y, z} from "@dbOperations" in /api/server.ts it won't work.

tsnode throws:

Error: Cannot find module '@dbOperations'

Any suggestions?

Answer 1

TypeScript only uses paths defined in tsconfig.json when compiling, but it doesn't actually output valid paths that are understandable for Node. You have to install tsconfig-paths to make it work.