Getting TypeError: foo_1.default is not a function

🐛 Bug Report

While refactoring a node project, I moved some files around (still in subfolders of src, adjusting the imports).

After doing so, I get an error when running tests of

Test suite failed to run TypeError: foo_1.default is not a function

(foo is my function, renamed for simplicity)

To Reproduce

jest.config.js:

module.exports = {
  "roots": [
    "<rootDir>/src"
  ],
  "transform": {
    "^.+\\.tsx?$": "ts-jest"
  },
}

tsconfig.json:

{
  "compilerOptions": {
    "target": "es5",                          
    "module": "commonjs",                     
    "lib": [ "es2017", "es2015.promise", "es2015.collection", "es5" ],
    "declaration": true,                      
    "outDir": "./build",
    "rootDir": "./src",                       
    "strict": true,                           
    "noImplicitAny": true,                    
    "strictNullChecks": true,                 
    "noImplicitThis": true,                   
    "alwaysStrict": true,                     
    "noUnusedLocals": false,                   
    "noUnusedParameters": false,               
    "noImplicitReturns": true,                
    "noFallthroughCasesInSwitch": true,
    "composite": true,
    "declarationMap": true,
    "sourceMap": true,
    "strictFunctionTypes": true,
    "strictPropertyInitialization": true
  }
}

The error occurs in module1.ts:

  import foo from './foo';
  const x = foo(bar);

Foo is defined in foo.ts:

export default function foo() {}

The test in question is in foo.spec.ts (all in the same directory):

import { bar } from './foo';

// Test bar, which does _not_ call foo()

• Other tests work.
• These tests worked until I moved the files (renamed the directory under src they were in).
• tsc works.
• Things I’ve tried:
  • Changing the import to a non-default (results in “TypeError: foo_1.foo is not a function”)
  • "allowSyntheticDefaultImports": true
  • "esModuleInterop": true
  • Updating ts-jest, Jest, and TypeScript to the latest versions
  • Using a moduleNameMapper (tsconfig-paths-jest and other permutations)

Expected behavior

The test works.

Link to repo (highly encouraged)

(Private/proprietary; can’t)

Debug log:

(Can’t include - references proprietary info)

envinfo

System:
    OS: MacOS Catalina

Npm packages:
   **(Note: I've tried upgrading all of these but node to the latest releases with no change.)**
    jest: 24.9.0
    ts-jest: 24.1.0
    typescript: 3.6.4
    babel(optional): n/a
    node: 12.16.3

Also reproduced with:
    "jest": "^26.3.0",
    "ts-jest": "^26.2.0",
    "typescript": "^3.9.7"

[TrueWill]

@ahnpnl I found the issue. In attempting to simplify to a small repo that would reproduce this, I found a circular reference.

• module1.ts imports from module2.ts
• module2.ts imports from module3.ts
• module3.ts imports from module1.ts

This works with tsc but fails with Jest + ts-jest.

Eliminating the circular reference (by moving one export to another module) resolved the issue. Thank you.

[ahnpnl]

normally the combination of allowSyntheticDefaultImports": true and esModuleInterop: true should solve the problem. But I don’t know exactly why it doesn’t work for that file.