feat(types): infer slots type from SetupContext in defineComponent by zhiyuanzmj · Pull Request #14688 · vuejs/core

zhiyuanzmj · 2026-04-06T16:18:41Z

Just like a functional component.

const Baz = defineComponent(
  <T,>(
    props: { foo: T },
    ctx: {
      slots: { default?: (props: { foo: T }) => any }
    },
  ) => () => slots.default?.(props),
)
const baz = new Baz({ foo: 1 })
baz.$slots.default({ foo: 1 })

Summary by CodeRabbit

New Features
- Enhanced TypeScript type inference for component slots. The framework now provides improved type support for slot definitions across different component patterns, enabling better type checking, autocomplete, and error detection in your IDE.
Tests
- Added comprehensive test cases to validate type inference for component slots across different setup patterns.

Summary by CodeRabbit

New Features
- Broader TypeScript slot typing for components, improving slot inference and editor autocomplete across options, setup, and functional component patterns.
Tests
- Added unit tests to validate slot type inference (including default slot call signatures) to catch regressions and ensure correct typings.

mergeProps Ensure event listeners that are explicitly null or undefined are preserved during prop merging instead of being dropped.

…slots

coderabbitai · 2026-04-06T16:19:06Z

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: d5f3143c-04b7-4f19-aee9-9a6489a5cd6d

📥 Commits

Reviewing files that changed from the base of the PR and between b98f262 and 3c92199.

📒 Files selected for processing (4)

packages-private/dts-test/defineComponent.test-d.tsx
packages/runtime-core/src/apiDefineComponent.ts
packages/runtime-core/src/component.ts
packages/runtime-core/src/componentPublicInstance.ts

✅ Files skipped from review due to trivial changes (1)

packages-private/dts-test/defineComponent.test-d.tsx

🚧 Files skipped from review as they are similar to previous changes (3)

packages/runtime-core/src/component.ts
packages/runtime-core/src/componentPublicInstance.ts
packages/runtime-core/src/apiDefineComponent.ts

📝 Walkthrough

Walkthrough

Broadened slot-related type generics to accept either SlotsType or a raw record across defineComponent and instance types; added conditional normalization so SetupContext.slots and component public instance $slots infer correctly. Added d.ts tests covering four defineComponent slot-inference scenarios.

Changes

Cohort / File(s)	Summary
Type Definition Updates `packages/runtime-core/src/apiDefineComponent.ts`, `packages/runtime-core/src/component.ts`, `packages/runtime-core/src/componentPublicInstance.ts`	Widened slot generics to `SlotsType
Type Inference Tests `packages-private/dts-test/defineComponent.test-d.tsx`	Added `describe('infer slots from \`SetupContext`')`with four`defineComponent`cases (option API and functional variants) asserting`this.$slots.default`/`instance.$slots.default`are not`any`and that calling the`default`slot with`{ foo: 1 }`type-checks. Also adjusted imports to include`EmitsOptions` in the initial vue type import and removed the later duplicate.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Suggested reviewers

jh-leong
johnsoncodehk

Poem

🐰 I hopped through types with nimble paws,
Widened slots without a pause.
Context whispers what props should be,
Tests confirm — hooray for me! 🎉

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main change: enhancing type inference for slots from SetupContext in defineComponent.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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github-actions · 2026-04-06T16:19:36Z

Size Report

Bundles

File	Size	Gzip	Brotli
runtime-dom.global.prod.js	105 kB	39.9 kB	35.8 kB
vue.global.prod.js	164 kB	59.9 kB	53.2 kB

Usages

Name	Size	Gzip	Brotli
createApp (CAPI only)	48.3 kB	18.8 kB	17.2 kB
createApp	56.5 kB	21.8 kB	20 kB
createSSRApp	60.7 kB	23.6 kB	21.5 kB
defineCustomElement	62.6 kB	23.8 kB	21.7 kB
overall	71 kB	27.2 kB	24.7 kB

pkg-pr-new · 2026-04-06T16:22:46Z

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commit: 3c92199

Copilot

Pull request overview

This PR updates runtime-core TypeScript typings to allow defineComponent / SetupContext slot typing to accept an “object slots” form (in addition to the existing SlotsType wrapper), and adds dts tests to cover the new inference path.

Changes:

Expand slot-related generics to accept SlotsType | Slots across SetupContext, defineComponent, and public instance typing.
Add conditional logic intended to map object-slot inputs back into SlotsType for $slots inference.
Add dts tests asserting $slots.default is not inferred as any when slots are provided via SetupContext.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
packages/runtime-core/src/componentPublicInstance.ts	Allows mixin public instance slot generic to accept `Slots` and conditionally wraps it.
packages/runtime-core/src/component.ts	Extends `SetupContext` slot generic and changes `ctx.slots` typing based on slot type form.
packages/runtime-core/src/apiDefineComponent.ts	Updates `defineComponent` overload generics/imports to accept `Slots` in addition to `SlotsType`.
packages-private/dts-test/defineComponent.test-d.tsx	Adds dts tests for slot inference flowing from `SetupContext` annotations.

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packages/runtime-core/src/component.ts

packages/runtime-core/src/componentPublicInstance.ts

packages-private/dts-test/defineComponent.test-d.tsx

coderabbitai

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@packages-private/dts-test/defineComponent.test-d.tsx`:
- Around line 1178-1247: The tests reference the Vue type EmitsOptions but it
isn't imported; update the import list from 'vue' to include EmitsOptions so the
usages in the SetupContext generic parameters (seen in the Foo, Bar, and Qux
defineComponent blocks) resolve correctly; ensure the top-of-file import
alongside defineComponent, SetupContext, IsAny, etc., includes EmitsOptions.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

Push a commit to this branch (recommended)
Create a new PR with the fixes

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 486d3e1f-0113-474a-bc03-d0f5761d5da6

📥 Commits

Reviewing files that changed from the base of the PR and between 9a2eb53 and 56092ef.

📒 Files selected for processing (4)

packages-private/dts-test/defineComponent.test-d.tsx
packages/runtime-core/src/apiDefineComponent.ts
packages/runtime-core/src/component.ts
packages/runtime-core/src/componentPublicInstance.ts

packages-private/dts-test/defineComponent.test-d.tsx

zhiyuanzmj added 3 commits March 10, 2026 21:53

fix(runtime-core): prevent removing undefined event handlers in

a04385c

mergeProps Ensure event listeners that are explicitly null or undefined are preserved during prop merging instead of being dropped.

feat(types): support object Slots type for defineComponent

b69cf4d

chore: merge remote-tracking branch 'origin/main' into setup-context-…

56092ef

…slots

Copilot AI review requested due to automatic review settings April 6, 2026 16:18

Copilot started reviewing on behalf of zhiyuanzmj April 6, 2026 16:19 View session

chore: update

16762ce

zhiyuanzmj added the scope: types label Apr 6, 2026

chore: update

6dc9ed7

Copilot AI reviewed Apr 6, 2026

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coderabbitai bot reviewed Apr 6, 2026

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packages-private/dts-test/defineComponent.test-d.tsx Show resolved Hide resolved

chore: update

b98f262

zhiyuanzmj changed the title ~~feat(types): support object slots type for defineComponent~~ feat(types): infer slots type from SetupContext in defineComponent Apr 7, 2026

zhiyuanzmj added 2 commits April 8, 2026 23:22

chore: update

94a719b

chore: update

3c92199

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feat(types): infer slots type from SetupContext in defineComponent#14688

feat(types): infer slots type from SetupContext in defineComponent#14688
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