Import error using Node with ES6 syntax #419
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ctavan
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Apr 29, 2020
BREAKING CHANGE: Native ES Modules is still an experimental API in
Node.js 14.0.0 and has so far not officially been supported by the
`uuid` module.
Since Node.js allows importing CommonJS modules it was possible to
import the `uuid` module like this:
```js
import uuid from 'uuid';
console.log(uuid.v4()); // -> 'cd6c3b08-0adc-4f4b-a6ef-36087a1c9869'
```
This will no longer work with proper ES Module exports in place. You
can now import the `uuid` library as described in the documentation:
```js
import { v4 as uuidv4 } from 'uuid';
uuidv4(); // ⇨ '9b1deb4d-3b7d-4bad-9bdd-2b0d7b3dcb6d'
```
or
```js
import * as uuid from 'uuid';
console.log(uuid.v4()); // -> 'cd6c3b08-0adc-4f4b-a6ef-36087a1c9869'
```
Enabling native ES Modules for Node.js requires some special care for
the v1 algorithm which needs internal state. This makes this library
susceptible to the dual package hazard described in
https://nodejs.org/docs/latest-v14.x/api/esm.html#esm_dual_commonjs_es_module_packages
While the "isolated state" solution seems to make more sense it causes
trouble with rollup which supports CommonJS files only with an
additional plugin, see rollup/rollup#3514.
It is worth noting that webpack could deal with the "isolated state"
solution since webpack supports CommonJS sources out of the box without
further plugins and also doesn't get confused by `.cjs` file extensions
that would have to be used in the state isolation approach for
compatibility with Node.js.
The wrapper approach should however work fine. Here's what code will be
used in each case:
1. Node.js `require('uuid')`
-> dist/index.js (CommonJS) -> dist/v1.js (CommonJS)
2. Node.js `import { v1 as uuidv1 } from 'uuid'`
-> wrapper.mjs (ESM) -> dist/v1.js (CommonJS)
3. rollup/webpack (targeting Node.js environments)
-> dist/esm-node/index.js (ESM) -> dist/esm-node/v1.js (ESM)
4. rollup/webpack (targeting Browser environments)
-> dist/esm-browser/index.js (ESM) -> dist/esm-browser/v1.js (ESM)
Fixes #245
Fixes #419
Fixes #342
|
@th1j5 we have just released |
|
Like a charm! |
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Was a bug report about using ES6 import syntax in Node
Since seeing this #245 (the last comments),
I would suggest updating the readme to explicitly state that it's not (yet #402 ) supported for Node.
This would prevent people from losing time on writing unnecessary bug reports ;)
Thanks!
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