Typescript Path not recognized in Jest Angular

## 🐛 Bug Report

versions jest ^23.1.0 types/jest ^22.2.23 jest-preset-angular ^5.2.2 jest-zone-patch ^0.0.8

Angular application Windows 10 computer VS code 1.23.1

Typescript 2.7.2

Context:

Typescript allows the use of paths in the tsconfig.json file such as

"baseUrl": "./src", 
"paths": {
  "@app/*": ["app/*"]
}

So the imports can be done this way: import { component } from “AT app/component” (note: AT is the at sign that I can’t insert here)

instead of import { Franchisee } from “…/…/…/component”

which makes for a more readable, easier to maintain code.

Bug: Jest fails any test using paths with this message:

Cannot find module ‘AT app/component’ from ‘component.spec.ts’ at Resolver.resolveModule (node_modules/jest-resolve/build/index.js:210:17) at Object.<anonymous> (src/app/component/component.spec.ts:11:20)

(note: AT is the at sign that I can’t insert here)

To Reproduce

Steps to reproduce the behavior: Configure tsconfig.ts with a path. In that path, change the import { component } from ‘./component’

to import { component } from ‘AT app/component’ (Same note, at symbol doesn’t get printed)

and welcome to the dance…

Expected behavior

Expected Jest to understand paths…

I have a ngrx platform example app using jest and also using paths and they work fine, but they refer to librarires (@ngrx/effects instead of …/…/ngrx/effects) for example.

Link to repl or repo

The repository https://github.com/mdelgadov/ngrx-platform the tsconfig.ts at the root directory has a path ATbooks for example-app/app/books the file example-app/app/books/containers/collection-page.component.spec.ts has ATbooks instead of …/ this is just an example for testing purposes.

Run yarn example:test and will receive the error

Cannot find module ‘@books/components/book-preview-list.component’ from ‘collection-page.component.spec.ts’

npx envinfo --preset jest

Paste the results here: C:\Users\mdelg\AppData\Roaming\npm-cache_npx\35952\node_modules\envinfo\dist\cli.js

System: OS: Windows 10 CPU: x64 Intel® Core™ i7-4790 CPU @ 3.60GHz Binaries: Yarn: 1.6.0 - C:\Program Files (x86)\Yarn\bin\yarn.CMD npm: 5.6.0 - C:\Program Files (x86)\nodejs\npm.CMD

[mdelgadov]

Yes, that was it! “moduleNameMapper”: { “^@books(.*)”: “<rootDir>/example-app/app/books/$1” },

did the trick…

thanks to thymikee and simenb and everybody else…

[latchezar-kostov-ascendlearning-com]

@mdelgadov I am running into the same issue and my struggling to come up with a solution.

"paths": { "@myscope/*": [ "libs/*/src", ] }

The lib/<name>/index.ts has all of the exports. What should the jest moduleNameMapper look like in order to be able to resolve these paths?