Can we generate a list with do expressions?

[kasperpeulen]

I was thinking about syntax like this:

<ul>
  {
    do* {
      for (let item of list) {
        yield <li>{item}</li>;
      }
    }
  }
</ul>

Or is something like this already possible?

[Jamesernator]

The semantics haven't been decided, I showed 3 possible options on the original gist but there's certainly other interpretations.

I'd expect though at the very least that if yield were allowed in do-expressions in some form that it would return a generator not an array, otherwise it'd be weirdly inconsistent with generator functions.

[kasperpeulen]

@Jamesernator Ah interesting. I also just found this proposal:
https://github.com/sebmarkbage/ecmascript-do-generator

I would expect it to return a generator as well, but maybe JSX could automatically convert the generator to an array.

[dead-claudia]

Related: #14

[jorendorff]

You might be interested in array comprehensions, previously proposed for ECMAScript, but ultimately rejected.

Currently, this can be done using the .map() method of Array objects:

<ul>
  {
    list.map(item => <li>{item}</li>)
  }
</ul>