Add extension to bin files

[lachrist]

Hi mocha team!

Using the --experimental-loader node flag with mocha bin will cause it to crash because it has no extension.

Example:

NODE_OPTIONS="--experimental-loader=./lib/loader.mjs" npx mocha
TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension "" for .../mocha/bin/mocha

Explanation:

More specifically, the --experimental-loader flag will cause node to pick the esm loader to load bin/mocha and it does not like file without extensions (unlike the cjs loader).

Solution:

Add ".js" extension to bin/mocha which would still allow to create a symbolic link at .bin/mocha without file extension.

[juergba]

@lachrist duplicate of #4645

Since --experimental-loader is still experimental and under redesign, we are not planning to add this extension to Mocha's binary for now. As a workaround you can move --experimental-loader=./lib/loader.mjs from NODE_OPTIONS to Mocha's config file .mocharc.js. Then Mocha will start a child-process with the entry point lib/cli/cli.js.

[lachrist]

Sorry for the duplicate!