Getting TypeError: foo_1.default is not a function

[TrueWill]

🐛 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"

[ahnpnl]

can you please try the latest version of ts-jest ?

[TrueWill]

@ahnpnl I have; I've updated ts-jest, jest, and typescript with no change.

[ahnpnl]

hmm this will be hard to check without any repos. Would you please try making a small repo for this issue ?

[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.

[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]

nice, I'm glad to hear that. So this issue can be also closed ?

[TrueWill]

@ahnpnl Yes, it can be closed (unless circular references are a thing you want to support). Thanks again.

[rogerprz]

@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.

Can you explain how you found this out? What did your code look like. I am not sure of the changes I need to make on mine.
For me i'm getting TypeError: dayjs_1.default is not a function
iamkun/dayjs#1667
Thanks

[Sakari369]

Solved this error by searching and fixing circular dependencies using Madge:
https://andrejsabrickis.medium.com/locate-circular-dependencies-in-typescript-modules-2b1eb03dbf2e

[pulpdood]

Found this on Google. I had this problem, but mine was probably an edge case: I had two files foo.ts and foo.json in the same directory and it was trying to grab the module from the JSON file. Just renamed the foo.json file and that fixed it.