From ee31e23f2be46545450927166b48d8994d593deb Mon Sep 17 00:00:00 2001
From: Evan You <yyx990803@gmail.com>
Date: Mon, 8 Apr 2019 16:43:31 +0800
Subject: [PATCH 1/3] functional and async components api change

---
 .../0000-functional-async-api-change.md       | 124 ++++++++++++++++++
 1 file changed, 124 insertions(+)
 create mode 100644 active-rfcs/0000-functional-async-api-change.md

diff --git a/active-rfcs/0000-functional-async-api-change.md b/active-rfcs/0000-functional-async-api-change.md
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+- Start Date: 2019-04-08
+- Target Major Version: 3.x
+- Reference Issues: N/A
+- Implementation PR: N/A
+
+# Summary
+
+- Functional components must be written as plain functions
+  - `{ functional: true }` option removed
+  - `<template functional>` no longer supported
+- Async component must be created via the `createAsyncComponent` API method
+
+# Basic example
+
+``` js
+import { h } from 'vue'
+
+const FunctionalComp = props => {
+  return h('div', `Hello! ${props.name}`)
+}
+```
+
+``` js
+import { createAsyncComponent } from 'vue'
+
+const AsyncComp = createAsyncComponent(() => import('./Foo.vue'))
+```
+
+# Motivation
+
+## Simplify Functional Components
+
+In 2.x, functional components must be created using the following format:
+
+``` js
+const FunctionalComp = {
+  functional: true,
+  render(h) {
+    return h('div', `Hello! ${props.name}`)
+  }
+}
+```
+
+This has the following issues:
+
+- Even when the component needs nothing but the render function, it still needs to use the object with `functional: true`.
+
+- Some options are supported (e.g. `props` and `inject`) but others are not (e.g. `components`). However, users often expect all options to be supported because it looks so similar to a normal stateful component (especially when they use SFC with `<template functional>`).
+
+Another aspect of the problem is that we've noticed some users are using functional components solely for performance reasons, e.g. in SFCs with `<template functional>`, and are requesting us to support more stateful component options in functional components. However, I don't think this is something we should invest more time in.
+
+In v3, the performance difference between stateful and functional components has been drastically reduced and will be insignificant in most use cases. As a result there is no longer a strong incentive to use functional components just for performance, which also no longer justifies the maintenance cost of supporting `<template functional>`. Functional components in v3 should be used primarily for simplicity, not performance.
+
+# Detailed Design
+
+In 3.x, we intend to support functional components **only** as plain functions:
+
+``` js
+import { h } from 'vue'
+
+const FunctionalComp = (props, slots) => {
+  return h('div', `Hello! ${props.name}`)
+}
+```
+
+- The `functional` option is removed, and object format with `{ functional: true }` is no longer supported.
+
+- SFCs will no longer support `<template functional>` - if you need anything more than a function, just use a normal component.
+
+- The function signature has also changed - `h` is now imported globally. Instead of a render context, props and slots and other values are passed in. For more details on how the new arguments can replace 2.x functional render context, see the [Render Function API Change RFC](TODO).
+
+## Runtime Props Validation
+
+Props declaration is now optional (only necessary when runtime validation is needed). To add runtime validation or default values, attach `props` to the function itself:
+
+``` js
+const FunctionalComp = props => {
+  return h('div', `Hello! ${props.name}`)
+}
+
+FunctionalComp.props = {
+  name: String
+}
+```
+
+## Async Component Creation
+
+With the functional component change, Vue's runtime won't be able to tell whether a function is being provided as a functional component or an async component factory. So in v3 async components must now be created via a new API method:
+
+``` js
+import { createAsyncComponent } from 'vue'
+
+const AsyncComp = createAsyncComponent(() => import('./Foo.vue'))
+```
+
+The method also supports advanced options:
+
+``` js
+const AsyncComp = createAsyncComponent({
+  factory: () => import('./Foo.vue'),
+  delay: 200,
+  timeout: 3000,
+  error: ErrorComponent,
+  loading: LoadingComponent
+})
+```
+
+This will make async component creation a little more verbose, but async component creation is typically a low-frequency use case, and are often grouped in the same file (the routing configuration).
+
+# Drawbacks
+
+- Migration cost
+
+# Alternatives
+
+N/A
+
+# Adoption strategy
+
+- For functional components, a compatibility mode can be provided for one-at-a-time migration.
+
+- For async components, the migration is straightforward and we can emit warnings when function components return Promise instead of VNodes.
+
+- SFCs using `<template functional>` should be converted to normal SFCs.

From 5d3c17cb222c80ac27c7a2561bf91af2aedeabd7 Mon Sep 17 00:00:00 2001
From: Evan You <yyx990803@gmail.com>
Date: Mon, 8 Apr 2019 17:01:01 +0800
Subject: [PATCH 2/3] update links

---
 active-rfcs/0000-functional-async-api-change.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/active-rfcs/0000-functional-async-api-change.md b/active-rfcs/0000-functional-async-api-change.md
index 1e7f6885..9b892d05 100644
--- a/active-rfcs/0000-functional-async-api-change.md
+++ b/active-rfcs/0000-functional-async-api-change.md
@@ -67,7 +67,7 @@ const FunctionalComp = (props, slots) => {
 
 - SFCs will no longer support `<template functional>` - if you need anything more than a function, just use a normal component.
 
-- The function signature has also changed - `h` is now imported globally. Instead of a render context, props and slots and other values are passed in. For more details on how the new arguments can replace 2.x functional render context, see the [Render Function API Change RFC](TODO).
+- The function signature has also changed - `h` is now imported globally. Instead of a render context, props and slots and other values are passed in. For more details on how the new arguments can replace 2.x functional render context, see the [Render Function API Change RFC](https://github.com/vuejs/rfcs/pull/28).
 
 ## Runtime Props Validation
 

From c95e4058a17510637bd3f120b5b5bfaa5702b5a3 Mon Sep 17 00:00:00 2001
From: Evan You <yyx990803@gmail.com>
Date: Tue, 12 Nov 2019 11:31:34 -0500
Subject: [PATCH 3/3] Adjust RFC ID

---
 ...al-async-api-change.md => 0007-functional-async-api-change.md} | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename active-rfcs/{0000-functional-async-api-change.md => 0007-functional-async-api-change.md} (100%)

diff --git a/active-rfcs/0000-functional-async-api-change.md b/active-rfcs/0007-functional-async-api-change.md
similarity index 100%
rename from active-rfcs/0000-functional-async-api-change.md
rename to active-rfcs/0007-functional-async-api-change.md