mocha and native ESM

[cspotcode]

Here is a working example of using mocha, ts-node, and node's native ESM module support.

https://github.com/TypeStrong/ts-node-repros/tree/mochajs-native-esm

Here are the logs proving that it works.

https://github.com/TypeStrong/ts-node-repros/runs/2041304936

[cspotcode]

If the example above can be improved, please share questions here so we can update it to address those questions.

[cspotcode]

@bennypowers

require() of /Users/bennyp/Developer/apollo-elements/packages/create/app.test.ts from /Users/bennyp/Developer/apollo-elements/node_modules/mocha/lib/mocha.js is an ES module file as it is a .ts file whose nearest parent package.json contains "type": "module" which defines all .ts files in that package scope as ES modules.

Looks like mocha is trying to require a .ts file when it should be importing it?

[bennypowers]

That would indeed appear to be the case

[cspotcode]

@bennypowers I see that you didn't include version numbers for all the moving parts in the information above.

[bennypowers]

$ node --version                                                                                                                                                                                         
v16.5.0
$ npx mocha --version
6.2.3
$ npx ts-node --version                                                                                                                                                                                  
v10.2.1
$ npx tsc --version                                                                                                                                                                                      
Version 4.3.5

[juergba]

Mocha v6.2.3: Mocha supports Node's native ESM since v7.1.0, the last version is v9.1.1.