TypeError: Unknown file extension ".ts" |

[Jason-Terry]

package.json

  "name": "sd-tracker-api",
  "version": "1.0.0",
  "description": "",
  "main": "main.ts",
  "scripts": {
    "build": "tsc -p .",
    "dev": "SET NODE_ENV=dev & ts-node-dev --respawn --transpile-only -r tsconfig-paths/register src/main.ts",
    "test": "SET NODE_ENV=test & mocha --check-leaks -r ts-node/register -r tsconfig-paths/register tests/**.spec.ts"
  },
  "author": "Jason Terry",
  "license": "ISC",
  "devDependencies": {
    "@types/chai": "^4.3.11",
    "@types/express": "^4.17.21",
    "@types/mocha": "^10.0.6",
    "@types/node": "^20.10.6",
    "@types/supertest": "^6.0.2",
    "chai": "^5.0.0",
    "mocha": "^10.2.0",
    "supertest": "^6.3.3",
    "ts-node": "^10.9.2",
    "ts-node-dev": "^2.0.0",
    "tsconfig-paths": "^4.2.0",
    "typescript": "^5.3.3"
  },
  "dependencies": {
    "dotenv": "^16.3.1",
    "express": "^4.18.2"
  }
}

tsconfig.json

{
  "exclude": ["./coverage", "./dist", "./node_modules"],
  "ts-node": {
    "transpileOnly": true,
    "files": true
  },
  "compilerOptions": {
    "target": "es2016", 
    "module": "Node16",  
    "rootDir": "./src",    
    "moduleResolution": "Node16",
    "baseUrl": "./src",
    "outDir": "./dist",
    "esModuleInterop": true,                             
    "forceConsistentCasingInFileNames": true,            
    "strict": true,                                      
    "skipLibCheck": true                                 
  }
}

.mocharc.json

{
  "extension": ["ts"],
  "spec": "tests/**/*.spec.ts",
  "require": "ts-node/register"
}

Greetings, I am unable to run mocha when including import { expect } from 'chai'; into my project.

It causes the following to occour.

npm run test

> sd-tracker-api@1.0.0 test
> SET NODE_ENV=test & mocha --check-leaks -r ts-node/register -r tsconfig-paths/register tests/**.spec.ts


TypeError: Unknown file extension ".ts" for E:\my-learning\sd-tracker-api\tests\types.spec.ts
    at Object.getFileProtocolModuleFormat [as file:] (node:internal/modules/esm/get_format:160:9)
    at defaultGetFormat (node:internal/modules/esm/get_format:203:36)
    at defaultLoad (node:internal/modules/esm/load:141:22)
    at async ModuleLoader.load (node:internal/modules/esm/loader:409:7)
    at async ModuleLoader.moduleProvider (node:internal/modules/esm/loader:291:45)
    at async link (node:internal/modules/esm/module_job:76:21)

I am not sure what to do to solve this? I followed the guidance of the following video along with the TS example project.

Video
Project

Any help would be greatly appreciated.

[huangjihua]

the same

[Sweet-PotEdos]

same here!

[AntonSweb]

same problem

[AntonSweb]

"loader=ts-node/esm" need to be added to the node-option in the mocha configuration

.mocharc.json

{
  "extension": [
    "ts"
  ],
  "spec": "tests/**/*.spec.ts",
  "require": [
    "ts-node/register"
  ],
  "node-option": [
    "loader=ts-node/esm"
  ],
  "recursive": true
}

[seventeen-yao]

This question comes from Chat.js 5.x, using 4.x will solve that.
chaijs/chai#1594 (reply in thread)

[sahin52]

it was related to chai in probably your example
please also check
chaijs/chai#1597

[sahin52]

I added esm to my command by loader=ts-node/esm, but now I'm getting typescript error which doesn't exist.

[JoshuaKGoldberg]

As of #76, we now have at least two working examples of using TypeScript with recent tools. You can see `packages/typescript-ts-node-esm-loader. Cheers! ☕

[sahin52]

In the example, package.json -> type is equal to module, but we weren't using that, which means it is a commonjs. The project doesn't work with module. Can you give an example where the package.json type is equal to commonjs? @JoshuaKGoldberg

[JoshuaKGoldberg]

packages/typescript-tsx-esm-import works on my machine if I switch it to "type": "commonjs" (or remove the "type": property altogether).

[sahin52]

After only removing "type" property in package.json, it did not work. Here is npm run test command result after removing type property

(node:2020) ExperimentalWarning: `--experimental-loader` may be removed in the future; instead use `register()`:
--import 'data:text/javascript,import { register } from "node:module"; import { pathToFileURL } from "node:url"; register("ts-node/esm", pathToFileURL("./"));'
(Use `node --trace-warnings ...` to show where the warning was created)
(node:2020) Warning: To load an ES module, set "type": "module" in the package.json or use the .mjs extension.

 Exception during run: C:\Users\Sahin\Desktop\Temp\mocha-examples\packages\typescript-ts-node-esm-loader\src\index.spec.ts:1
import { equal } from "assert";
^^^^^^

SyntaxError: Cannot use import statement outside a module

node version: v21.6.2, npm version: 10.2.4

But I changed the file extensions to .mts and changed the imports etc accordingly. It now works with this configuration.
Here is the commit for it: sahin52@ced4f98

[JoshuaKGoldberg]

This is rapidly descending into becoming a support thread, which GitHub issues on an examples repo are not well suited for. Your best bet would be to ask in one of Mocha's support forums: the Mocha Discord's #help channel or Stackoverflow's mocha tag. 🙂