Simple configuration to set up jest and typescript with its custom paths 📁🧪

jest.config.js

const { pathsToModuleNameMapper } = require('ts-jest');
//const { pathsToModuleNameMapper } = require('ts-jest/utils'); // also you can do like this, but jest recommends use one above
const { compilerOptions } = require('./tsconfig.json');

/** @type {import('ts-jest/dist/types').InitialOptionsTsJest} */
module.exports = {
  preset: 'ts-jest',
  testEnvironment: 'node',
  coverageDirectory: './coverage',
  testMatch: [ "**/?(*.)+(test).ts" ],
  resetMocks: true,
  clearMocks: true,
  moduleNameMapper: pathsToModuleNameMapper(compilerOptions.paths, { prefix: '<rootDir>/src' })
}

tsconfig.json

{
  "compilerOptions": {
    "target": "esnext",
    "module": "commonjs",
    "strict": true,
    "declaration": true,
    "noImplicitAny": true,
    "removeComments": true,
    "esModuleInterop": true,
    "resolveJsonModule": true,
    "traceResolution": true,
    "strictPropertyInitialization": false,
    "declarationDir": "./lib",
    "outDir": "./dist",
    "rootDir": ".",
    "baseUrl": "src",
    "paths": {
      "@/*": [ "./*" ],
      "@models": [ "interfaces/barrel.ts" ]
    },
  },
  "include": [ "src/**/*" ],
  "exclude": [ "node_modules" ]
}

Good practice?

I actually don't know if custom paths are good practices, because you want to test ts files, not js files. And tests are usually excluded in the tsconfig.json, so I think that the custom paths should not be used in the tests files. That's my assumption.

tsconfig.json

{
  "compilerOptions": {
    "baseUrl": "src",
    "paths": { "@/*": [ "./*" ] }
  },
  "include": [ "src/**/*" ],
  "exclude": [ 
    "node_modules", 
    "**/*.test.ts", 
    "**/*.spec.ts" 
  ]
}