Extend with-data-prefetch to handle advanced use cases (#3525)

examples/with-data-prefetch/components/link.js

@@ -5,6 +5,34 @@ import { execOnce, warn } from 'next/dist/lib/utils'
 import exact from 'prop-types-exact'
 import { format, resolve, parse } from 'url'
 
+export const prefetch = async (href) => {
+  // if  we're running server side do nothing
+  if (typeof window === 'undefined') return
+
+  const url =
+    typeof href !== 'string'
+      ? format(href)
+      : href
+
+  const { pathname } = window.location
+
+  const parsedHref = resolve(pathname, url)
+
+  const { query } =
+    typeof href !== 'string'
+      ? href
+      : parse(url, true)
+
+  const Component = await Router.prefetch(parsedHref)
+
+  // if Component exists and has getInitialProps
+  // fetch the component props (the component should save it in cache)
+  if (Component && Component.getInitialProps) {
+    const ctx = { pathname: href, query, isVirtualCall: true }
+    await Component.getInitialProps(ctx)
+  }
+}
+
 // extend default next/link to customize the prefetch behaviour
 export default class LinkWithData extends Link {
   // re defined Link propTypes to add `withData`
@@ -33,32 +61,16 @@ export default class LinkWithData extends Link {
 
   // our custom prefetch method
   async prefetch () {
-    // if the prefetch prop is not defined or
-    // we're running server side do nothing
+    // if the prefetch prop is not defined do nothing
     if (!this.props.prefetch) return
-    if (typeof window === 'undefined') return
 
-    const url =
-      typeof this.props.href !== 'string'
-        ? format(this.props.href)
-        : this.props.href
-
-    const { pathname } = window.location
-
-    const href = resolve(pathname, url)
-
-    const { query } =
-      typeof this.props.href !== 'string'
-        ? this.props.href
-        : parse(url, true)
-
-    const Component = await Router.prefetch(href)
-
-    // if withData prop is defined, Component exists and has getInitialProps
-    // fetch the component props (the component should save it in cache)
-    if (this.props.withData && Component && Component.getInitialProps) {
-      const ctx = { pathname: href, query, isVirtualCall: true }
-      await Component.getInitialProps(ctx)
+    // if withData prop is defined
+    // prefetch with data
+    // otherwise just prefetch the page
+    if (this.props.withData) {
+      prefetch(this.props.href)
+    } else {
+      super.prefetch()
     }
   }
 }

examples/with-data-prefetch/pages/index.js

@@ -1,4 +1,4 @@
-import Link from '../components/link'
+import Link, { prefetch } from '../components/link'
 
 // we just render a list of 3 articles having 2 with prefetched data
 export default () => (
@@ -16,8 +16,8 @@ export default () => (
         </Link>
       </li>
       <li>
-        <Link href='/article?id=3' prefetch withData>
-          <a>Article 3</a>
+        <Link href='/article?id=3' >
+          <a onMouseOver={e => prefetch('/article?id=3')} >Article 3</a>
         </Link>
       </li>
     </ul>