Could not find a declaration file for module 'ava'. 'node_modules/ava/entrypoints/main.mjs' implicitly has an 'any' type.

[linaGirl]

My test code is written in TypeScript but the type declarations cannot be found when using ava version 4. With ava version 3 it seems to work. This is probably due to the missing index.js file in the ava package?

Test file: tests/my.test.ts

import test from 'ava';

run:

node ./node_modules/.bin/tsc

output:

tests/my.test.ts:1:18 - error TS7016: Could not find a declaration file for module 'ava'. 'node_modules/ava/entrypoints/main.mjs' implicitly has an 'any' type.
  Try `npm i --save-dev @types/ava` if it exists or add a new declaration (.d.ts) file containing `declare module 'ava';`

1 import test from 'ava';
                   ~~~~~


Found 1 error in tests/my.test.ts:1

package.json

{
  "type": "module",
  "name": "test",
  "version": "1.0.0",
  "devDependencies": {
    "@ava/typescript": "^3.0.1",
    "@tsconfig/node16": "^1.0.2",
    "@types/node": "^17.0.5",
    "ava": "^4.0.0",
    "eslint": "^8.6.0",
    "typescript": "^4.6.0-dev.20220105"
  },
  "scripts": {
    "build": "node ./node_modules/.bin/tsc",
    "test": "node ./node_modules/.bin/tsc && ava"
  }
}

ava.config.js

export default {
    "typescript": {
        "rewritePaths": {
            "tests/": "build/tests/"
        },
        "compile": false
    }
}

tsconfig.json

{
  "extends": "@tsconfig/node16/tsconfig.json",
  "compilerOptions": {
    "preserveConstEnums": true,
    "outDir": "build",
    "strictPropertyInitialization": false,
    "target": "es2021",
    "module": "nodenext",
    "strict": true,
    "esModuleInterop": true,
    "forceConsistentCasingInFileNames": true,
    "sourceMap": true,
    "declaration": true
  },
  "include": ["tests/**/*"],
  "exclude": ["node_modules", "**/*.spec.ts"]
}

Maybe i'm missing something. I'm happy to provide a repo for reproducing the problem.

[novemberborn]

What happens with a stable TypeScript version, rather than a pre-release?

[linaGirl]

Thanks @novemberborn it works with the stable version

[novemberborn]

Fingers crossed then it's a TS bug that'll go away before final release.

[t2t2]

With typescript 4.7 release seems like it's still an issue when the project has "type": "module" and tsconfig's "module": "NodeNext" (well, and strict mode, otherwise it will just warn and doesn't give any autocomplete info)

  Uncaught exception in tests\sample.test.ts

  tests/sample.test.ts(1,18): error TS7016: Could not find a declaration file for module 'ava'. '.../ava-ts-module/node_modules/ava/entrypoints/main.cjs' implicitly has an 'any' type.    Try `npm i --save-dev @types/ava` if it exists or add a new declaration (.d.ts) file containing `declare module 'ava';`
  tests/sample.test.ts(3,18): error TS7006: Parameter 't' implicitly has an 'any' type.

minimal repo:

package.json:

{
  "name": "ava-ts-module",
  "type": "module",
  "version": "1.0.0",
  "scripts": {
    "test": "ava"
  },
  "devDependencies": {
    "ava": "^4.2.0",
    "ts-node": "^10.8.0",
    "typescript": "^4.7.2"
  },
  "ava": {
    "extensions": {
      "ts": "module"
    },
    "nodeArguments": [
      "--loader=ts-node/esm"
    ]
  }
}

tsconfig.json

{
  "compilerOptions": {
    "module": "NodeNext",
    "strict": true
  }
}

tests\sample.test.ts

import test from 'ava';

test('one test', t => {
	t.pass();
});

Seems like adding "types": "./index.d.ts" to exports map is makes it work, but probably also needs types for other exports

[novemberborn]

@t2t2 see #3024.