folding range support

[BigBoulard]

Hi guys,

In a Svelte file, when params of a function are not on the same line, I can't fold the whole function. I can instead only fold the function params.

async function lambda(
    param1,
    param2,
    param3
  ) {
	const a = 1;
	const b = 2;
}

becomes

async function lambda(
  ) {
  const a = 1;
  const b = 2;
}

instead of

async function lambda() {}

Unlike .svelte files, it works perfectly on .js ones.

[jasonlyu123]

We'll need to implement the folding range feature for this. The current one is an indent-based solution provided by VSCode.

Haven't tried it yet. But I am not sure if the result would be great given we have some limitations with our current approach for typescript features. We might not be able to calculate the folding range when there are syntax errors in the markup. I suspect this would cause the folded range suddenly expand. If it did it is worse than not being able to fold a function.

I did some POC and it seems like VSCode did have some logic to retain folded range. I think we can add this in the future. But since there's already an indent-based solution for folding, We'll probably put this in a lower priority.