feat(nuxt): refresh override for data fetching composables

docs/content/1.getting-started/6.data-fetching.md

@@ -147,6 +147,12 @@ function next() {
 
 The key to making this work is to call the `refresh()` method returned from the `useFetch()` composable when a query parameter has changed.
 
+By default, `refresh()` will not make a new request if one is already pending. You can override any pending requests with the override option. Previous requests will not be cancelled, but their result will not update the data or pending state - and any previously awaited promises will not resolve until this new request resolves.
+
+```js
+refresh({ override: true })
+```
+
 ### `refreshNuxtData`
 
 Invalidate the cache of `useAsyncData`, `useLazyAsyncData`, `useFetch` and `useLazyFetch` and trigger the refetch.

docs/content/3.api/1.composables/use-async-data.md

@@ -27,7 +27,7 @@ type AsyncDataOptions<DataT> = {
 }
 
 interface RefreshOptions {
-  _initial?: boolean
+  override?: boolean
 }
 
 type AsyncData<DataT, ErrorT> = {

docs/content/3.api/1.composables/use-fetch.md

@@ -30,7 +30,7 @@ type UseFetchOptions = {
 type AsyncData<DataT> = {
   data: Ref<DataT>
   pending: Ref<boolean>
-  refresh: () => Promise<void>
+  refresh: (opts?: { override?: boolean }) => Promise<void>
   execute: () => Promise<void>
   error: Ref<Error | boolean>
 }

packages/nuxt/src/app/composables/asyncData.ts

@@ -34,6 +34,12 @@ export interface AsyncDataOptions<
 
 export interface AsyncDataExecuteOptions {
   _initial?: boolean
+  /**
+   * Force a refresh, even if there is already a pending request. Previous requests will
+   * not be cancelled, but their result will not affect the data/pending state - and any
+   * previously awaited promises will not resolve until this new request resolves.
+   */
+  override?: boolean
 }
 
 export interface _AsyncData<DataT, ErrorT> {
@@ -115,17 +121,20 @@ export function useAsyncData<
   const asyncData = { ...nuxt._asyncData[key] } as AsyncData<DataT, DataE>
 
   asyncData.refresh = asyncData.execute = (opts = {}) => {
-    // Avoid fetching same key more than once at a time
     if (nuxt._asyncDataPromises[key]) {
-      return nuxt._asyncDataPromises[key]
+      if (!opts.override) {
+        // Avoid fetching same key more than once at a time
+        return nuxt._asyncDataPromises[key]
+      }
+      (nuxt._asyncDataPromises[key] as any).cancelled = true
     }
     // Avoid fetching same key that is already fetched
     if (opts._initial && useInitialCache()) {
       return nuxt.payload.data[key]
     }
     asyncData.pending.value = true
     // TODO: Cancel previous promise
-    nuxt._asyncDataPromises[key] = new Promise<DataT>(
+    const promise = new Promise<DataT>(
       (resolve, reject) => {
         try {
           resolve(handler(nuxt))
@@ -134,6 +143,9 @@ export function useAsyncData<
         }
       })
       .then((result) => {
+        // If this request is cancelled, resolve to the latest request.
+        if ((promise as any).cancelled) { return nuxt._asyncDataPromises[key] }
+
         if (options.transform) {
           result = options.transform(result)
         }
@@ -144,17 +156,23 @@ export function useAsyncData<
         asyncData.error.value = null
       })
       .catch((error: any) => {
+        // If this request is cancelled, resolve to the latest request.
+        if ((promise as any).cancelled) { return nuxt._asyncDataPromises[key] }
+
         asyncData.error.value = error
         asyncData.data.value = unref(options.default?.() ?? null)
       })
       .finally(() => {
+        if ((promise as any).cancelled) { return }
+
         asyncData.pending.value = false
         nuxt.payload.data[key] = asyncData.data.value
         if (asyncData.error.value) {
           nuxt.payload._errors[key] = true
         }
         delete nuxt._asyncDataPromises[key]
       })
+    nuxt._asyncDataPromises[key] = promise
     return nuxt._asyncDataPromises[key]
   }
 

packages/nuxt/src/app/composables/fetch.ts

@@ -86,8 +86,12 @@ export function useFetch<
     ]
   }
 
+  let controller: AbortController
+
   const asyncData = useAsyncData<_ResT, ErrorT, Transform, PickKeys>(key, () => {
-    return $fetch(_request.value, _fetchOptions) as Promise<_ResT>
+    controller?.abort?.()
+    controller = typeof AbortController !== 'undefined' ? new AbortController() : {} as AbortController
+    return $fetch(_request.value, { signal: controller.signal, ..._fetchOptions }) as Promise<_ResT>
   }, _asyncDataOptions)
 
   return asyncData

test/basic.test.ts

@@ -670,6 +670,10 @@ describe.skipIf(isWindows)('useAsyncData', () => {
     await $fetch('/useAsyncData/refresh')
   })
 
+  it('requests can be cancelled/overridden', async () => {
+    await expectNoClientErrors('/useAsyncData/override')
+  })
+
   it('two requests made at once resolve and sync', async () => {
     await expectNoClientErrors('/useAsyncData/promise-all')
   })

test/fixtures/basic/pages/useAsyncData/override.vue

@@ -0,0 +1,36 @@
+<template>
+  <div>
+    Override
+    {{ data }}
+  </div>
+</template>
+
+<script setup lang="ts">
+let count = 0
+let timeout = 0
+const { data, refresh } = await useAsyncData(() => process.server ? Promise.resolve(1) : new Promise(resolve => setTimeout(() => resolve(++count), timeout)))
+
+if (count || data.value !== 1) {
+  throw new Error('Data should be unset')
+}
+
+timeout = 100
+const p = refresh()
+
+if (process.client && (count !== 0 || data.value !== 1)) {
+  throw new Error('count should start at 0')
+}
+
+timeout = 0
+await refresh({ override: true })
+
+if (process.client && (count !== 1 || data.value !== 1)) {
+  throw new Error('override should execute')
+}
+
+await p
+
+if (process.client && (count !== 2 || data.value !== 1)) {
+  throw new Error('cancelled promise should not affect data')
+}
+</script>