From 54c57e3987f87aa2be0d6ad15995302bf907baa7 Mon Sep 17 00:00:00 2001
From: pooya parsa <pyapar@gmail.com>
Date: Tue, 12 Oct 2021 00:36:50 +0200
Subject: [PATCH] feat(nuxt3): `useFetch` (#721)

---
 .../content/3.docs/1.usage/1.data-fetching.md | 55 ++++++++++++++++---
 examples/use-fetch/nuxt.config.ts             |  4 ++
 examples/use-fetch/package.json               | 12 ++++
 examples/use-fetch/pages/index.vue            |  9 +++
 examples/use-fetch/server/api/hello.ts        |  3 +
 packages/bridge/src/auto-imports.ts           |  3 +-
 packages/nitro/src/build.ts                   |  3 +-
 packages/nitro/types/fetch.d.ts               |  6 +-
 .../nuxt3/src/app/composables/asyncData.ts    | 53 +++++++++++++++---
 packages/nuxt3/src/app/composables/fetch.ts   | 44 +++++++++++++++
 packages/nuxt3/src/app/composables/index.ts   |  1 +
 .../nuxt3/src/auto-imports/identifiers.ts     |  3 +-
 yarn.lock                                     |  8 +++
 13 files changed, 182 insertions(+), 22 deletions(-)
 create mode 100644 examples/use-fetch/nuxt.config.ts
 create mode 100644 examples/use-fetch/package.json
 create mode 100644 examples/use-fetch/pages/index.vue
 create mode 100644 examples/use-fetch/server/api/hello.ts
 create mode 100644 packages/nuxt3/src/app/composables/fetch.ts

diff --git a/docs/content/3.docs/1.usage/1.data-fetching.md b/docs/content/3.docs/1.usage/1.data-fetching.md
index cdad0a6637..9cf3adfb7b 100644
--- a/docs/content/3.docs/1.usage/1.data-fetching.md
+++ b/docs/content/3.docs/1.usage/1.data-fetching.md
@@ -1,10 +1,10 @@
 # Data Fetching
 
-Nuxt provides `useAsyncData` to handle data fetching within your application.
+Nuxt provides `useFetch` and `useAsyncData` to handle data fetching within your application.
 
 ## `useAsyncData`
 
-Within your pages and components you can use `useAsyncData` to get access to data that resolves asynchronously.
+Within your pages, components and plugins you can use `useAsyncData` to get access to data that resolves asynchronously.
 
 ### Usage
 
@@ -17,12 +17,19 @@ useAsyncData(key: string, fn: () => Object, options?: { defer: boolean, server:
 * **options**:
   - _defer_: whether to load the route before resolving the async function (defaults to `false`)
   - _server_: whether the fetch the data on server-side (defaults to `true`)
+  - _transform_: A function that can be used to alter fn result after resolving
+  - _pick_: Only pick specified keys in this array from fn result
 
 Under the hood, `defer: false` uses `<Suspense>` to block the loading of the route before the data has been fetched. Consider using `defer: true` and implementing a loading state instead for a snappier user experience.
 
 ### Example
 
-```vue
+```js [server/api/index.ts]
+let counter = 0
+export default () => ++counter
+```
+
+```vue [pages/index.vue]
 <script setup>
 const { data } = await useAsyncData('time', () => $fetch('/api/count'))
 </script>
@@ -32,6 +39,42 @@ const { data } = await useAsyncData('time', () => $fetch('/api/count'))
 </template>
 ```
 
+## `useFetch`
+
+Within your pages, components and plugins you can use `useFetch` to get universally fetch from any URL.
+
+This composable provides a convenient wrapper around `useAsyncData` and `$fetch` and automatically generates a key based on url and fetch options and infers API response type.
+
+Usage:
+
+```ts
+useFetch(url: string, options?)
+```
+
+Available options:
+- `key`: Provide a custom key
+- Options from [ohmyfetch](https://github.com/unjs/ohmyfetch)
+  - `method`: Request method
+  - `params`: Query params
+  - `baseURL`: Base URL for request
+- Options from `useAsyncDaa`
+  - `defer`
+  - `server`
+  - `pick`
+  - `transform`
+
+### Example
+
+```vue [pages/index.vue]
+<script setup>
+const { data } = await useFetch('/api/count')
+</script>
+
+<template>
+  Page visits: {{ data.count }}
+</template>
+```
+
 ### Best practices
 
 As seen in [Concepts > Data fetching](/concepts/data-fetching), the data returned by `useAsyncData` will be stored inside the page payload. This mean that every key returned that is not used in your component will be added to the payload.
@@ -54,13 +97,11 @@ Imagine that `/api/mountains/everest` returns the following object:
 }
 ```
 
-If you plan to only use `title` and `description` in your component, you can select the keys by chaining the result of `$fetch`:
+If you plan to only use `title` and `description` in your component, you can select the keys by chaining the result of `$fetch` or `pick` option:
 
 ```vue
 <script setup>
-const { data: mountain } = await useAsyncData('everest', () =>
-  $fetch('/api/mountains/everest').then(({ title, description }) => ({ title, description }))
-)
+const { data: mountain } = await useFetch('/api/mountains/everest', { pick: ['title', 'description'] })
 </script>
 
 <template>
diff --git a/examples/use-fetch/nuxt.config.ts b/examples/use-fetch/nuxt.config.ts
new file mode 100644
index 0000000000..a3e4d68096
--- /dev/null
+++ b/examples/use-fetch/nuxt.config.ts
@@ -0,0 +1,4 @@
+import { defineNuxtConfig } from 'nuxt3'
+
+export default defineNuxtConfig({
+})
diff --git a/examples/use-fetch/package.json b/examples/use-fetch/package.json
new file mode 100644
index 0000000000..2bc976a2d3
--- /dev/null
+++ b/examples/use-fetch/package.json
@@ -0,0 +1,12 @@
+{
+  "name": "example-use-fetch",
+  "private": true,
+  "devDependencies": {
+    "nuxt3": "latest"
+  },
+  "scripts": {
+    "dev": "nuxt dev",
+    "build": "nuxt build",
+    "start": "node .output/server/index.mjs"
+  }
+}
diff --git a/examples/use-fetch/pages/index.vue b/examples/use-fetch/pages/index.vue
new file mode 100644
index 0000000000..9753a68a7c
--- /dev/null
+++ b/examples/use-fetch/pages/index.vue
@@ -0,0 +1,9 @@
+<template>
+  <div>
+    Server response: {{ data }}
+  </div>
+</template>
+
+<script setup>
+const { data } = await useFetch('/api/hello', { params: { foo: 'bar' } })
+</script>
diff --git a/examples/use-fetch/server/api/hello.ts b/examples/use-fetch/server/api/hello.ts
new file mode 100644
index 0000000000..9e7524dce3
--- /dev/null
+++ b/examples/use-fetch/server/api/hello.ts
@@ -0,0 +1,3 @@
+import { useQuery } from 'h3'
+
+export default req => ({ query: useQuery(req) })
diff --git a/packages/bridge/src/auto-imports.ts b/packages/bridge/src/auto-imports.ts
index 3e8aed6c75..927d714525 100644
--- a/packages/bridge/src/auto-imports.ts
+++ b/packages/bridge/src/auto-imports.ts
@@ -4,7 +4,8 @@ import autoImports from '../../nuxt3/src/auto-imports/module'
 // TODO: implement these: https://github.com/nuxt/framework/issues/549
 const disabled = [
   'useAsyncData',
-  'asyncData'
+  'asyncData',
+  'useFetch'
 ]
 
 const identifiers = {
diff --git a/packages/nitro/src/build.ts b/packages/nitro/src/build.ts
index b02a4542fb..cc0d434601 100644
--- a/packages/nitro/src/build.ts
+++ b/packages/nitro/src/build.ts
@@ -55,7 +55,6 @@ export async function build (nitroContext: NitroContext) {
 
   nitroContext.rollupConfig = getRollupConfig(nitroContext)
   await nitroContext._internal.hooks.callHook('nitro:rollup:before', nitroContext)
-  await writeTypes(nitroContext)
   return nitroContext._nuxt.dev ? _watch(nitroContext) : _build(nitroContext)
 }
 
@@ -89,6 +88,7 @@ async function writeTypes (nitroContext: NitroContext) {
 
 async function _build (nitroContext: NitroContext) {
   nitroContext.scannedMiddleware = await scanMiddleware(nitroContext._nuxt.serverDir)
+  await writeTypes(nitroContext)
 
   consola.start('Building server...')
   const build = await rollup(nitroContext.rollupConfig).catch((error) => {
@@ -151,4 +151,5 @@ async function _watch (nitroContext: NitroContext) {
       }
     }
   )
+  await writeTypes(nitroContext)
 }
diff --git a/packages/nitro/types/fetch.d.ts b/packages/nitro/types/fetch.d.ts
index b530117b09..720f38eefd 100644
--- a/packages/nitro/types/fetch.d.ts
+++ b/packages/nitro/types/fetch.d.ts
@@ -23,9 +23,9 @@ export declare type TypedInternalResponse<Route, Default> =
         : MiddlewareOf<Route>
       : Default
 
-export declare interface $Fetch {
-  <T = unknown, R extends FetchRequest = FetchRequest> (request: R, opts?: FetchOptions): Promise<TypedInternalResponse<R, T>>
-  raw<T = unknown, R extends FetchRequest = FetchRequest> (request: R, opts?: FetchOptions): Promise<FetchResponse<TypedInternalResponse<R, T>>>
+export declare interface $Fetch<T = unknown, R extends FetchRequest = FetchRequest> {
+  (request: R, opts?: FetchOptions): Promise<TypedInternalResponse<R, T>>
+  raw (request: R, opts?: FetchOptions): Promise<FetchResponse<TypedInternalResponse<R, T>>>
 }
 
 declare global {
diff --git a/packages/nuxt3/src/app/composables/asyncData.ts b/packages/nuxt3/src/app/composables/asyncData.ts
index e197db069a..37668eddc6 100644
--- a/packages/nuxt3/src/app/composables/asyncData.ts
+++ b/packages/nuxt3/src/app/composables/asyncData.ts
@@ -2,24 +2,44 @@ import { onBeforeMount, onUnmounted, ref } from 'vue'
 import type { Ref } from 'vue'
 import { NuxtApp, useNuxtApp } from '#app'
 
-export interface AsyncDataOptions<T> {
+export type _Transform<Input=any, Output=any> = (input: Input) => Output
+
+export type PickFrom<T, K extends Array<string>> = T extends Record<string, any> ? Pick<T, K[number]> : T
+export type KeysOf<T> = Array<keyof T extends string ? T : string>
+export type KeyOfRes<Transform extends _Transform> = KeysOf<ReturnType<Transform>>
+
+export interface AsyncDataOptions<
+  DataT,
+  Transform extends _Transform<DataT, any> = _Transform<DataT, DataT>,
+  PickKeys extends KeyOfRes<_Transform> = KeyOfRes<Transform>
+  > {
   server?: boolean
   defer?: boolean
-  default?: () => T
+  default?: () => DataT
+  transform?: Transform
+  pick?: PickKeys
 }
 
-export interface _AsyncData<T> {
-  data: Ref<T>
+export interface _AsyncData<DataT> {
+  data: Ref<DataT>
   pending: Ref<boolean>
   refresh: (force?: boolean) => Promise<void>
   error?: any
 }
 
-export type AsyncData<T> = _AsyncData<T> & Promise<_AsyncData<T>>
+export type AsyncData<Data> = _AsyncData<Data> & Promise<_AsyncData<Data>>
 
 const getDefault = () => null
 
-export function useAsyncData<T extends Record<string, any>> (key: string, handler: (ctx?: NuxtApp) => Promise<T>, options: AsyncDataOptions<T> = {}): AsyncData<T> {
+export function useAsyncData<
+  DataT,
+  Transform extends _Transform<DataT> = _Transform<DataT, DataT>,
+  PickKeys extends KeyOfRes<Transform> = KeyOfRes<Transform>
+> (
+  key: string,
+  handler: (ctx?: NuxtApp) => Promise<DataT>,
+  options: AsyncDataOptions<DataT, Transform, PickKeys> = {}
+) : AsyncData<PickFrom<ReturnType<Transform>, PickKeys>> {
   // Validate arguments
   if (typeof key !== 'string') {
     throw new TypeError('asyncData key must be a string')
@@ -51,7 +71,7 @@ export function useAsyncData<T extends Record<string, any>> (key: string, handle
     data: ref(nuxt.payload.data[key] ?? options.default()),
     pending: ref(true),
     error: ref(null)
-  } as AsyncData<T>
+  } as AsyncData<DataT>
 
   asyncData.refresh = (force?: boolean) => {
     // Avoid fetching same key more than once at a time
@@ -63,6 +83,12 @@ export function useAsyncData<T extends Record<string, any>> (key: string, handle
     // TODO: Handle immediate errors
     nuxt._asyncDataPromises[key] = Promise.resolve(handler(nuxt))
       .then((result) => {
+        if (options.transform) {
+          result = options.transform(result)
+        }
+        if (options.pick) {
+          result = pick(result, options.pick) as DataT
+        }
         asyncData.data.value = result
         asyncData.error.value = null
       })
@@ -108,8 +134,17 @@ export function useAsyncData<T extends Record<string, any>> (key: string, handle
   }
 
   // Allow directly awaiting on asyncData
-  const asyncDataPromise = Promise.resolve(nuxt._asyncDataPromises[key]).then(() => asyncData) as AsyncData<T>
+  const asyncDataPromise = Promise.resolve(nuxt._asyncDataPromises[key]).then(() => asyncData) as AsyncData<DataT>
   Object.assign(asyncDataPromise, asyncData)
 
-  return asyncDataPromise as AsyncData<T>
+  // @ts-ignore
+  return asyncDataPromise as AsyncData<DataT>
+}
+
+function pick (obj: Record<string, any>, keys: string[]) {
+  const newObj = {}
+  for (const key of keys) {
+    newObj[key] = obj[key]
+  }
+  return newObj
 }
diff --git a/packages/nuxt3/src/app/composables/fetch.ts b/packages/nuxt3/src/app/composables/fetch.ts
new file mode 100644
index 0000000000..0b949d55d7
--- /dev/null
+++ b/packages/nuxt3/src/app/composables/fetch.ts
@@ -0,0 +1,44 @@
+import type { FetchOptions } from 'ohmyfetch'
+import type { $Fetch } from '@nuxt/nitro'
+import type { AsyncDataOptions, _Transform, KeyOfRes } from './asyncData'
+import { useAsyncData } from './asyncData'
+
+export type Awaited<T> = T extends Promise<infer U> ? U : T
+export type FetchResult<ReqT extends string> = Awaited<ReturnType<$Fetch<unknown, ReqT>>>
+
+export type UseFetchOptions<
+  DataT,
+  Transform extends _Transform<DataT, any> = _Transform<DataT, DataT>,
+  PickKeys extends KeyOfRes<Transform> = KeyOfRes<Transform>
+> = AsyncDataOptions<DataT, Transform, PickKeys> & FetchOptions & { key?: string }
+
+export function useFetch<
+    ReqT extends string = string,
+    ResT = FetchResult<ReqT>,
+    Transform extends (res: ResT) => any = (res: ResT) => ResT,
+    PickKeys extends KeyOfRes<Transform> = KeyOfRes<Transform>
+  > (
+  url: ReqT,
+  opts: UseFetchOptions<ResT, Transform, PickKeys> = {}
+) {
+  if (!opts.key) {
+    const keys: any = { u: url }
+    if (opts.baseURL) {
+      keys.b = opts.baseURL
+    }
+    if (opts.method && opts.method.toLowerCase() !== 'get') {
+      keys.m = opts.method.toLowerCase()
+    }
+    if (opts.params) {
+      keys.p = opts.params
+    }
+    opts.key = generateKey(keys)
+  }
+
+  return useAsyncData('$f' + opts.key, () => $fetch(url, opts) as Promise<ResT>, opts)
+}
+
+// TODO: More predictable universal hash
+function generateKey (keys) {
+  return JSON.stringify(keys).replace(/[{":}=/,]|https?:\/\//g, '_').replace(/_+/g, '_')
+}
diff --git a/packages/nuxt3/src/app/composables/index.ts b/packages/nuxt3/src/app/composables/index.ts
index 5f499638fd..14c2d9bce8 100644
--- a/packages/nuxt3/src/app/composables/index.ts
+++ b/packages/nuxt3/src/app/composables/index.ts
@@ -2,3 +2,4 @@ export { defineNuxtComponent } from './component'
 export { useAsyncData } from './asyncData'
 export { useHydration } from './hydrate'
 export { useState } from './state'
+export { useFetch } from './fetch'
diff --git a/packages/nuxt3/src/auto-imports/identifiers.ts b/packages/nuxt3/src/auto-imports/identifiers.ts
index 099b3f3199..5ad7d45056 100644
--- a/packages/nuxt3/src/auto-imports/identifiers.ts
+++ b/packages/nuxt3/src/auto-imports/identifiers.ts
@@ -5,7 +5,8 @@ const identifiers = {
     'useNuxtApp',
     'defineNuxtPlugin',
     'useRuntimeConfig',
-    'useState'
+    'useState',
+    'useFetch'
   ],
   '#meta': [
     'useMeta'
diff --git a/yarn.lock b/yarn.lock
index a10e89876e..44e794adb7 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -9230,6 +9230,14 @@ __metadata:
   languageName: unknown
   linkType: soft
 
+"example-use-fetch@workspace:examples/use-fetch":
+  version: 0.0.0-use.local
+  resolution: "example-use-fetch@workspace:examples/use-fetch"
+  dependencies:
+    nuxt3: latest
+  languageName: unknown
+  linkType: soft
+
 "example-use-state@workspace:examples/use-state":
   version: 0.0.0-use.local
   resolution: "example-use-state@workspace:examples/use-state"