未找到 Jest 测试模块

Question

I'm testing my js app with jest . In my package.json I map all the modules like described in the documentation :

 "jest": {
    "moduleNameMapper": {
      "@db/(.*)": "<rootDir>/db/$1",
      "@src/(.*)": "<rootDir>/src/$1",
      "@dto/(.*)": "<rootDir>/src/dto/$1",
      "@repos/(.*)": "<rootDir>/src/repos/$1",
      "@fetchers/(.*)": "<rootDir>/src/fetchers/$1",
      "@controllers/(.*)": "<rootDir>/src/controllers/$1",
      "@parsers/(.*)": "<rootDir>/src/parsers/$1",
      "@streams/(.*)": "<rootDir>/src/streams/$1",
      "@validators/(.*)": "<rootDir>/src/validators/$1"
    }
  },

However when I instantiate a new RestRepo that contains an import at the top, I get this error when I execute the test:

Cannot find module '@db' from 'RestRepo.js'

Require stack:
  src/repos/RestRepo.js
  tests/unit/RestEndpoint.test.js

> 1 | const { RestEndpoint } = require('@db');
    |                          ^
  2 | 
  3 | class RestRepo {

How can I fix this and why is this happening?

Answer 1

You can try replacing

"@db/(.*)": "<rootDir>/db/$1",

with

"@db(.*)": "<rootDir>/db$1",

this way the capturing group will match an optional slash / if present and

require("@db")

will be interpreted as

require("<rootDir>/db");

---

Or just add another entry

"@db": "<rootDir>/db",