Error When Including Module From Mapped Path

Hi there, I’m getting an error when trying to load a module from a mapped path. The error is as follows:

    Cannot find module '@app/constants/actionTypes' from 'index.ts'
      
      at Resolver.resolveModule (node_modules/jest-resolve/build/index.js:151:17)
      at Object.<anonymous> (src/actions/auth/index.ts:3:69)
      at Object.<anonymous> (src/actions/auth/spec.ts:4:15)

And I’m trying to do the following:

import * as actionTypes from "@app/constants/actionTypes";

The file definitely exists and worked with relative paths.

Here’s my tsconfig.json:

{
    "compilerOptions": {
        "outDir": "./dist/",
        "sourceMap": true,
        "noImplicitAny": true,
        "module": "commonjs",
        "target": "es5",
        "jsx": "react",
        "baseUrl": ".",
        "paths": {
            "@app/*": [ "./src/*" ]
        }
    },
    "filesGlob": [
        "src/**/*.ts",
        "src/**/*.tsx",
        "src/*.ts",
        "src/*.tsx"
    ],
    "exclude": [
        "node_modules"
    ]
}

And here’s the jest configuration of package.json;

  "jest": {
    "moduleFileExtensions": [
      "ts",
      "tsx",
      "js"
    ],
    "transform": {
      ".(ts|tsx)": "<rootDir>/node_modules/ts-jest/preprocessor.js"
    },
    "testResultsProcessor": "<rootDir>/node_modules/ts-jest/coverageprocessor.js",
    "testRegex": "(/test/.*|(test|spec))\\.(ts|tsx)$",
    "collectCoverage": true,
    "collectCoverageFrom": [
      "src/**/*.{ts,tsx}"
    ],
    "moduleDirectories": [
      "node_modules",
      "src"
    ]
  }

As you can see, I’m including the moduleDirectories, as suggested.

What’s weirder still, is that I can still reference other modules through that path, and the following runs without error:

import { RequestLogin, ResponseError, ResponseAuth } from "@app/models/api";

Compiling directly with tsc and with the --traceResolution flag it seems to resolve without issue:

======== Resolving module '@app/constants/actionTypes' from '/var/www/front-end/src/actions/auth/index.ts'. ========
'baseUrl' option is set to '/var/www/front-end', using this value to resolve non-relative module name '@app/constants/actionTypes'
'paths' option is specified, looking for a pattern to match module name '@app/constants/actionTypes'.
Module name '@app/constants/actionTypes', matched pattern '@app/*'.
Trying substitution './src/*', candidate module location: './src/constants/actionTypes'.
Loading module as file / folder, candidate module location '/var/www/front-end/src/constants/actionTypes'.
File '/var/www/front-end/src/constants/actionTypes.ts' exist - use it as a name resolution result.
Resolving real path for '/var/www/front-end/src/constants/actionTypes.ts', result '/var/www/front-end/src/constants/actionTypes.ts'
======== Module name '@app/constants/actionTypes' was successfully resolved to '/var/www/front-end/src/constants/actionTypes.ts'. ========

It’s baffling me as I can’t work out why it would affect one module, but not the other.

Thanks for your help.

[kulshekhar]

@archy-bold add the following to the jest section in your package.json

    "moduleNameMapper": {
      "@app/(.*)": "<rootDir>/src/$1"
    }

This should solve the issue

[vcardins]

Hi, by setting the src folder in moduleDirectories just worked fine for me.