error when redeclaring variables with `var`

[leonidaz]

Describe the bug

I'm working on a function that takes a parameter and either creates a signal variable with $state() or $state.raw().

However, the only way to do this for the same variable is to use var. However, this doesn't work because Svelte complains that variable has already been declared. This is perfectly allowed in Javascript of course. Obviously, it's not a good practice in general but in terms of being able to declare signal for the same variable this would be the only way currently.

<script>
  function doSomething (init, type = 'deep') {
    if (type === 'raw') {
      var myState = $state.raw(init);
    } else {
      var myState = $state(init)
    }

    // .......
  }
</script>

Error compiling
`myState` has already been declared

Ideally, I'd like to be able to use a ternary operator to assign. Wonder if this can be identified in the parser...

<script>
  let myState = type === 'raw' ? $state.raw(init) : $state(init);
</script>

It seems the only way to accomplish this is to have two signal variables and resort to using if conditions when reading or updating them which is quite annoying.

Reproduction

Playground reproduction

Logs

No response

System Info

Playground

Severity

annoyance

[Rich-Harris]

For Svelte to work, it needs to know what type of thing a given binding is. As things stand the compiler can say, with certainty, that foo is a derived and bar is a prop and so on. Remember, runes aren't functions except in a syntactic sense — they're part of the declaration itself.

[leonidaz]

right, runes are compiled away, just thought that somehow this can be recognized but yeah, I think I see what you mean with everything else in the code.