Is it possible for svelte typescript to not distinguish between type-only imports and normal imports like vue?

[rxliuli]

For example, the code below can work in Vue

// App.vue
<script setup lang="ts">
import { onMounted } from 'vue'
import { add, Add } from './utils'

onMounted(() => {
  const f: Add = add
  console.log(f(1, 2))
})
</script>

<template>
  <h1>Hello World</h1>
</template>

Similar code does not work properly in svelte

<script lang="ts">
  import { onMount } from 'svelte'
  import { add, Add } from './utils'

  onMount(() => {
    const f: Add = add
    console.log(f(1, 2))
  })
</script>

<h1>Hello World</h1>

A compilation error will appear: 'Add' is a type and must be imported using a type-only import when 'verbatimModuleSyntax' is enabled, and a runtime error: Uncaught SyntaxError: The requested module '/src/utils.ts' does not provide an export named 'Add'. Since Vue has already achieved this, shouldn't the Svelte compiler, as a similar template language, be able to do it too?

[brunnerh]

As far as I know the types are only stripped during processing/compilation, not analyzed, which is why these explicit instructions are required. (Type checking is done separately via svelte-check.)

[rxliuli]

The issue is that types can be stripped without explicit instructions, after all, all type exports are declared in one of the following two ways, which can be detected. See vuejs/core#3183

export interface TypeA {}

export type TypeB = {}

[dominikg]

while we might be able to I don't think it would be a good idea. Being explicit with imports is good for static analysis tools and provides important context when reading a file as a human. Its just 5 chars and should also be automatically generated for imports added by your ide, is this really something you need? Why?

[rxliuli]

Well, since it's not a default option in TypeScript, regular TypeScript code doesn't deliberately distinguish between them. In Svelte, if it only leads to TypeScript compilation errors, that seems fine, but it also produces a runtime error, which makes the issue look like a bug. This issue was also discussed in Vue 3, and they resolved it 3 years ago. vuejs/core#3183
The auto-import feature of IDE is not always configured correctly. For example, in wxt's official template project, "useDefineForClassFields": true is not configured, which leads to incorrect auto-imports in svelte components. Although this could be considered a configuration issue with the wxt template, but...

Kapture.2024-12-06.at.19.25.45.mp4