utils: fix ESM import

[ocavue]

Fixes an incorrect import for ESM.

[paulmillr]

the question is: why have all tests been passing?

[ocavue]

I should able to answer this question but I'm now in the bed so I will check it out tomorrow.

[paulmillr]

0.5.1 is out

[ocavue]

why have all tests been passing

When importing a relative ESM file, ESM always requires the file extension. For example, Node.js in CommonJS module accepts both require('./bar.js') and require('./bar'), but Node.js in ESM only accepts import './bar.js'.

The test (test/index.js) is a CommonJS file, so it won't fail when the file extension (.js) is missing.

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To prevent this issue, the simplest solution would be changing the moduleResolution from bundler to Node16 in tsconfig.esm.json, and add src/package.json with the content as {"type": "module"}.

When using "moduleResolution": "Node16", tsc would output CommonJS or ESM code based on the type field in the nearest package.josn. If the type is "module", then tsc would generate ESM code and also check the file extension, described above.

Another solution would be using a bundler to handle the rewrite of file extension. This requires more change though.

[ocavue]

Update: I've submitted a PR to set modeResolution to Node16.

#27