fix(svelte5): update typings to support new component types (#400)

Author: mcous

Diff for: .github/workflows/release.yml

@@ -34,7 +34,7 @@ jobs:
           # We only need to lint once, so do it on latest Node and Svelte
           - { node: '20', svelte: '4', check: 'lint' }
           # `SvelteComponent` is not generic in Svelte 3, so type-checking only passes in >= 4
-          - { node: '20', svelte: '4', check: 'types' }
+          - { node: '20', svelte: '4', check: 'types:legacy' }
           - { node: '20', svelte: 'next', check: 'types' }
           # Only run Svelte 5 checks on latest Node
           - { node: '20', svelte: 'next', check: 'test:vitest:jsdom' }

Diff for: package.json

@@ -70,6 +70,7 @@
     "test:vitest:happy-dom": "vitest run --coverage --environment happy-dom",
     "test:jest": "npx --node-options=\"--experimental-vm-modules --no-warnings\" jest --coverage",
     "types": "svelte-check",
+    "types:legacy": "svelte-check --tsconfig tsconfig.legacy.json",
     "validate": "npm-run-all test:vitest:* test:jest types build",
     "build": "tsc -p tsconfig.build.json",
     "contributors:add": "all-contributors add",

Diff for: src/__tests__/fixtures/Mounter.svelte

@@ -16,4 +16,4 @@
   })
 </script>
 
-<button></button>
+<button>click me</button>

Diff for: src/__tests__/fixtures/Simple.svelte renamed to src/__tests__/fixtures/Typed.svelte

@@ -1,6 +1,8 @@
 <script lang="ts">
   export let name: string
   export let count: number
+
+  export const hello: string = 'hello'
 </script>
 
 <h1>hello {name}</h1>

Diff for: src/__tests__/fixtures/TypedRunes.svelte

@@ -0,0 +1,8 @@
+<script lang="ts">
+  const { name, count }: { name: string; count: number } = $props()
+
+  export const hello: string = 'hello'
+</script>
+
+<h1>hello {name}</h1>
+<p>count: {count}</p>

Diff for: src/__tests__/render-runes.test-d.ts

@@ -0,0 +1,39 @@
+import { expectTypeOf } from 'expect-type'
+import { describe, test } from 'vitest'
+
+import * as subject from '../index.js'
+import Component from './fixtures/TypedRunes.svelte'
+
+describe('types', () => {
+  test('render is a function that accepts a Svelte component', () => {
+    subject.render(Component, { name: 'Alice', count: 42 })
+    subject.render(Component, { props: { name: 'Alice', count: 42 } })
+  })
+
+  test('rerender is a function that accepts partial props', async () => {
+    const { rerender } = subject.render(Component, { name: 'Alice', count: 42 })
+
+    await rerender({ name: 'Bob' })
+    await rerender({ count: 0 })
+  })
+
+  test('invalid prop types are rejected', () => {
+    // @ts-expect-error: name should be a string
+    subject.render(Component, { name: 42 })
+
+    // @ts-expect-error: name should be a string
+    subject.render(Component, { props: { name: 42 } })
+  })
+
+  test('render result has container and component', () => {
+    const result = subject.render(Component, { name: 'Alice', count: 42 })
+
+    expectTypeOf(result).toMatchTypeOf<{
+      container: HTMLElement
+      component: { hello: string }
+      debug: (el?: HTMLElement) => void
+      rerender: (props: { name?: string; count?: number }) => Promise<void>
+      unmount: () => void
+    }>()
+  })
+})

Diff for: src/__tests__/types.test-d.ts renamed to src/__tests__/render-utilities.test-d.ts

@@ -1,45 +1,12 @@
 import { expectTypeOf } from 'expect-type'
-import type { ComponentProps, SvelteComponent } from 'svelte'
 import { describe, test } from 'vitest'
 
 import * as subject from '../index.js'
-import Simple from './fixtures/Simple.svelte'
-
-describe('types', () => {
-  test('render is a function that accepts a Svelte component', () => {
-    subject.render(Simple, { name: 'Alice', count: 42 })
-    subject.render(Simple, { props: { name: 'Alice', count: 42 } })
-  })
-
-  test('rerender is a function that accepts partial props', async () => {
-    const { rerender } = subject.render(Simple, { name: 'Alice', count: 42 })
-
-    await rerender({ name: 'Bob' })
-    await rerender({ count: 0 })
-  })
-
-  test('invalid prop types are rejected', () => {
-    // @ts-expect-error: name should be a string
-    subject.render(Simple, { name: 42 })
-
-    // @ts-expect-error: name should be a string
-    subject.render(Simple, { props: { name: 42 } })
-  })
-
-  test('render result has container and component', () => {
-    const result = subject.render(Simple, { name: 'Alice', count: 42 })
-
-    expectTypeOf(result).toMatchTypeOf<{
-      container: HTMLElement
-      component: SvelteComponent<{ name: string }>
-      debug: (el?: HTMLElement) => void
-      rerender: (props: Partial<ComponentProps<Simple>>) => Promise<void>
-      unmount: () => void
-    }>()
-  })
+import Component from './fixtures/Comp.svelte'
 
+describe('render query and utility types', () => {
   test('render result has default queries', () => {
-    const result = subject.render(Simple, { name: 'Alice', count: 42 })
+    const result = subject.render(Component, { name: 'Alice' })
 
     expectTypeOf(result.getByRole).parameters.toMatchTypeOf<
       [role: subject.ByRoleMatcher, options?: subject.ByRoleOptions]
@@ -55,8 +22,8 @@ describe('types', () => {
       () => ''
     )
     const result = subject.render(
-      Simple,
-      { name: 'Alice', count: 42 },
+      Component,
+      { name: 'Alice' },
       { queries: { getByVibes } }
     )
 

Diff for: src/__tests__/render.test-d.ts

@@ -0,0 +1,39 @@
+import { expectTypeOf } from 'expect-type'
+import { describe, test } from 'vitest'
+
+import * as subject from '../index.js'
+import Component from './fixtures/Typed.svelte'
+
+describe('types', () => {
+  test('render is a function that accepts a Svelte component', () => {
+    subject.render(Component, { name: 'Alice', count: 42 })
+    subject.render(Component, { props: { name: 'Alice', count: 42 } })
+  })
+
+  test('rerender is a function that accepts partial props', async () => {
+    const { rerender } = subject.render(Component, { name: 'Alice', count: 42 })
+
+    await rerender({ name: 'Bob' })
+    await rerender({ count: 0 })
+  })
+
+  test('invalid prop types are rejected', () => {
+    // @ts-expect-error: name should be a string
+    subject.render(Component, { name: 42 })
+
+    // @ts-expect-error: name should be a string
+    subject.render(Component, { props: { name: 42 } })
+  })
+
+  test('render result has container and component', () => {
+    const result = subject.render(Component, { name: 'Alice', count: 42 })
+
+    expectTypeOf(result).toMatchTypeOf<{
+      container: HTMLElement
+      component: { hello: string }
+      debug: (el?: HTMLElement) => void
+      rerender: (props: { name?: string; count?: number }) => Promise<void>
+      unmount: () => void
+    }>()
+  })
+})

Diff for: src/component-types.d.ts

@@ -0,0 +1,43 @@
+import type * as Svelte from 'svelte'
+
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+type IS_MODERN_SVELTE = any extends Svelte.Component ? false : true
+
+/** A compiled, imported Svelte component. */
+export type Component<P> = IS_MODERN_SVELTE extends true
+  ? Svelte.Component<P> | Svelte.SvelteComponent<P>
+  : Svelte.SvelteComponent<P>
+
+/**
+ * The type of an imported, compiled Svelte component.
+ *
+ * In Svelte 4, this was the Svelte component class' type.
+ * In Svelte 5, this distinction no longer matters.
+ */
+export type ComponentType<C> = C extends Svelte.SvelteComponent
+  ? Svelte.ComponentType<C>
+  : C
+
+/** The props of a component. */
+export type Props<C> = Svelte.ComponentProps<C>
+
+/**
+ * The exported fields of a component.
+ *
+ * In Svelte 4, this is simply the instance of the component class.
+ * In Svelte 5, this is the set of variables marked as `export`'d.
+ */
+export type Exports<C> = C extends Svelte.SvelteComponent
+  ? C
+  : C extends Svelte.Component<unknown, infer E>
+    ? E
+    : never
+
+/**
+ * Options that may be passed to `mount` when rendering the component.
+ *
+ * In Svelte 4, these are the options passed to the component constructor.
+ */
+export type MountOptions<C> = IS_MODERN_SVELTE extends true
+  ? Parameters<typeof Svelte.mount<Props<C>, Exports<C>>>[1]
+  : Svelte.ComponentConstructorOptions<Props<C>>

Diff for: src/pure.js

@@ -13,8 +13,8 @@ const componentCache = new Set()
 /**
  * Customize how Svelte renders the component.
  *
- * @template {import('svelte').SvelteComponent} C
- * @typedef {import('svelte').ComponentProps<C> | Partial<import('svelte').ComponentConstructorOptions<import('svelte').ComponentProps<C>>>} SvelteComponentOptions
+ * @template {import('./component-types.js').Component} C
+ * @typedef {import('./component-types.js').Props<C> | Partial<import('./component-types.js').MountOptions<C>>} SvelteComponentOptions
  */
 
 /**
@@ -30,15 +30,15 @@ const componentCache = new Set()
 /**
  * The rendered component and bound testing functions.
  *
- * @template {import('svelte').SvelteComponent} C
+ * @template {import('./component-types.js').Component} C
  * @template {import('@testing-library/dom').Queries} [Q=typeof import('@testing-library/dom').queries]
  *
  * @typedef {{
  *   container: HTMLElement
  *   baseElement: HTMLElement
- *   component: C
+ *   component: import('./component-types.js').Exports<C>
  *   debug: (el?: HTMLElement | DocumentFragment) => void
- *   rerender: (props: Partial<import('svelte').ComponentProps<C>>) => Promise<void>
+ *   rerender: (props: Partial<import('./component-types.js').Props<C>>) => Promise<void>
  *   unmount: () => void
  * } & {
  *   [P in keyof Q]: import('@testing-library/dom').BoundFunction<Q[P]>
@@ -48,10 +48,10 @@ const componentCache = new Set()
 /**
  * Render a component into the document.
  *
- * @template {import('svelte').SvelteComponent} C
+ * @template {import('./component-types.js').Component} C
  * @template {import('@testing-library/dom').Queries} [Q=typeof import('@testing-library/dom').queries]
  *
- * @param {import('svelte').ComponentType<C>} Component - The component to render.
+ * @param {import('./component-types.js').ComponentType<C>} Component - The component to render.
  * @param {SvelteComponentOptions<C>} options - Customize how Svelte renders the component.
  * @param {RenderOptions<Q>} renderOptions - Customize how Testing Library sets up the document and binds queries.
  * @returns {RenderResult<C, Q>} The rendered component and bound testing functions.

Diff for: tsconfig.legacy.json

@@ -0,0 +1,8 @@
+{
+  "extends": ["./tsconfig.json"],
+  "exclude": [
+    "src/__tests__/render-runes.test-d.ts",
+    "src/__tests__/fixtures/CompRunes.svelte",
+    "src/__tests__/fixtures/TypedRunes.svelte"
+  ]
+}