feat: lazy fn option

src/data-loaders/createDataLoader.ts

@@ -93,7 +93,12 @@ export interface DefineDataLoaderOptionsBase<isLazy extends boolean> {
    *
    * @defaultValue `false`
    */
-  lazy?: isLazy
+  lazy?:
+    | isLazy
+    | ((
+        to: RouteLocationNormalizedLoaded,
+        from?: RouteLocationNormalizedLoaded
+      ) => boolean)
 
   /**
    * Whether this loader should be awaited on the server side or not. Combined with the `lazy` option, this gives full
@@ -118,6 +123,18 @@ export interface DefineDataLoaderOptionsBase<isLazy extends boolean> {
   errors?: Array<new (...args: any) => any>
 }
 
+export const toLazyValue = (
+  lazy:
+    | boolean
+    | undefined
+    | ((
+        to: RouteLocationNormalizedLoaded,
+        from?: RouteLocationNormalizedLoaded
+      ) => boolean),
+  to: RouteLocationNormalizedLoaded,
+  from?: RouteLocationNormalizedLoaded
+) => (typeof lazy === 'function' ? lazy(to, from) : lazy)
+
 /**
  * When the data should be committed to the entry.
  * - `immediate`: the data is committed as soon as it is loaded.
@@ -200,13 +217,15 @@ export interface UseDataLoaderInternals<
   /**
    * Loads the data from the cache if possible, otherwise loads it from the loader and awaits it.
    *
-   * @param route - route location to load the data for
+   * @param to - route location to load the data for
    * @param router - router instance
+   * @param from - route location we are coming from
    * @param parent - parent data loader entry
    */
   load: (
-    route: RouteLocationNormalizedLoaded,
+    to: RouteLocationNormalizedLoaded,
     router: Router,
+    from?: RouteLocationNormalizedLoaded,
     parent?: DataLoaderEntryBase
   ) => Promise<void>
 

src/data-loaders/defineColadaLoader.ts

@@ -41,6 +41,7 @@ import {
   type UseQueryReturn,
   useQuery,
 } from '@pinia/colada'
+import { toLazyValue } from './createDataLoader'
 
 /**
  * Creates a data loader composable that can be exported by pages to attach the data loading to a route. This returns a
@@ -93,6 +94,7 @@ export function defineColadaLoader<Data, isLazy extends boolean>(
   function load(
     to: RouteLocationNormalizedLoaded,
     router: Router,
+    from?: RouteLocationNormalizedLoaded,
     parent?: DataLoaderEntryBase,
     reload?: boolean
   ): Promise<void> {
@@ -229,7 +231,7 @@ export function defineColadaLoader<Data, isLazy extends boolean>(
             entry.stagedError = newError
             // propagate error if non lazy or during SSR
             // NOTE: Cannot be handled at the guard level because of nested loaders
-            if (!options.lazy || isSSR) {
+            if (!toLazyValue(options.lazy, to, from) || isSSR) {
               throw newError
             }
           } else {
@@ -352,7 +354,7 @@ export function defineColadaLoader<Data, isLazy extends boolean>(
       // )
       router[APP_KEY].runWithContext(() =>
         // in this case we always need to run the functions for nested loaders consistency
-        load(route, router, parentEntry, true)
+        load(route, router, undefined, parentEntry, true)
       )
     }
 
@@ -399,14 +401,14 @@ export function defineColadaLoader<Data, isLazy extends boolean>(
       isLoading,
       reload: (to: RouteLocationNormalizedLoaded = router.currentRoute.value) =>
         router[APP_KEY].runWithContext(() =>
-          load(to, router, undefined, true)
+          load(to, router, undefined, undefined, true)
         ).then(() => entry!.commit(to)),
       // pinia colada
       refetch: (
         to: RouteLocationNormalizedLoaded = router.currentRoute.value
       ) =>
         router[APP_KEY].runWithContext(() =>
-          load(to, router, undefined, true)
+          load(to, router, undefined, undefined, true)
         ).then(() => entry!.commit(to)),
       refresh: (
         to: RouteLocationNormalizedLoaded = router.currentRoute.value

src/data-loaders/defineLoader.ts

@@ -29,6 +29,7 @@ import {
 } from 'unplugin-vue-router/runtime'
 
 import { shallowRef } from 'vue'
+import { toLazyValue } from './createDataLoader'
 
 /**
  * Creates a data loader composable that can be exported by pages to attach the data loading to a route. This returns a
@@ -88,6 +89,7 @@ export function defineBasicLoader<Data, isLazy extends boolean>(
   function load(
     to: RouteLocationNormalizedLoaded,
     router: Router,
+    from?: RouteLocationNormalizedLoaded,
     parent?: DataLoaderEntryBase
   ): Promise<void> {
     const entries = router[LOADER_ENTRIES_KEY]!
@@ -197,7 +199,7 @@ export function defineBasicLoader<Data, isLazy extends boolean>(
           entry.stagedError = e
           // propagate error if non lazy or during SSR
           // NOTE: Cannot be handled at the guard level because of nested loaders
-          if (!options.lazy || isSSR) {
+          if (!toLazyValue(options.lazy, to, from) || isSSR) {
             throw e
           }
         }
@@ -309,7 +311,9 @@ export function defineBasicLoader<Data, isLazy extends boolean>(
       // console.log(
       //   `🔁 loading from useData for "${options.key}": "${route.fullPath}"`
       // )
-      router[APP_KEY].runWithContext(() => load(route, router, parentEntry))
+      router[APP_KEY].runWithContext(() =>
+        load(route, router, undefined, parentEntry)
+      )
     }
 
     entry = entries.get(loader)!

src/data-loaders/navigation-guard.ts

@@ -17,7 +17,7 @@ import type {
   Router,
 } from 'vue-router'
 import { type _Awaitable } from '../utils'
-import { type UseDataLoader } from './createDataLoader'
+import { toLazyValue, type UseDataLoader } from './createDataLoader'
 
 /**
  * TODO: export functions that allow preloading outside of a navigation guard
@@ -131,7 +131,7 @@ export function setupLoaderGuard({
     })
   })
 
-  const removeDataLoaderGuard = router.beforeResolve((to) => {
+  const removeDataLoaderGuard = router.beforeResolve((to, from) => {
     // if we reach this guard, all properties have been set
     const loaders = Array.from(to.meta[LOADER_SET_KEY]!) as UseDataLoader[]
 
@@ -154,13 +154,13 @@ export function setupLoaderGuard({
           app
             // allows inject and provide APIs
             .runWithContext(() =>
-              loader._.load(to as RouteLocationNormalizedLoaded, router)
+              loader._.load(to as RouteLocationNormalizedLoaded, router, from)
             )
         )!
 
         // on client-side, lazy loaders are not awaited, but on server they are
         // we already checked for the `server` option above
-        return !isSSR && lazy
+        return !isSSR && toLazyValue(lazy, to, from)
           ? undefined
           : // return the non-lazy loader to commit changes after all loaders are done
             ret.catch((reason) =>
@@ -196,7 +196,7 @@ export function setupLoaderGuard({
 
   // listen to duplicated navigation failures to reset the pendingTo and pendingLoad
   // since they won't trigger the beforeEach or beforeResolve defined above
-  const removeAfterEach = router.afterEach((to, _from, failure) => {
+  const removeAfterEach = router.afterEach((to, from, failure) => {
     // console.log(
     //   `🔚 afterEach "${_from.fullPath}" -> "${to.fullPath}": ${failure?.message}`
     // )
@@ -223,7 +223,10 @@ export function setupLoaderGuard({
           // lazy loaders do not block the navigation so the navigation guard
           // might call commit before the loader is ready
           // on the server, entries might not even exist
-          if (entry && (!lazy || !entry.isLoading.value)) {
+          if (
+            entry &&
+            (!toLazyValue(lazy, to, from) || !entry.isLoading.value)
+          ) {
             entry.commit(to as RouteLocationNormalizedLoaded)
           }
         }