fix(view): add passing props to inactive component (#2773)

Closes #2301

* fix(router-view): add passing props to inactive component

* test(keep-alive): add more cases for props

* test(keep-alive): adapt tests

* refactor(view): rename function

Co-authored-by: Eduardo San Martin Morote <posva@users.noreply.github.com>

examples/keepalive-view/app.js

@@ -27,7 +27,52 @@ const IndexChild2 = { template: '<div>index child2</div>' }
 
 const Home = { template: '<div>home</div>' }
 
-const ViewWithKeepalive = { template: '<keep-alive><router-view></router-view></keep-alive>' }
+const ViewWithKeepalive = {
+  template: '<keep-alive><router-view></router-view></keep-alive>'
+}
+
+const Parent = { template: '<div>msg: {{ msg }}<router-view /></div>', props: ['msg'] }
+
+const RequiredProps = {
+  template: '<div>props from route config is: {{ msg }}</div>',
+  props: {
+    msg: {
+      type: String,
+      required: true
+    }
+  }
+}
+
+// keep original values to restore them later
+const originalSilent = Vue.config.silent
+const originalWarnHandler = Vue.config.warnHandler
+
+const CatchWarn = {
+  template: `<div>{{ didWarn ? 'caught missing prop warn' : 'no missing prop warn' }}</div>`,
+  data () {
+    return {
+      didWarn: false
+    }
+  },
+  beforeRouteEnter (to, from, next) {
+    let missPropWarn = false
+    Vue.config.silent = false
+    Vue.config.warnHandler = function (msg, vm, trace) {
+      if (/Missing required prop/i.test(msg)) {
+        missPropWarn = true
+      }
+    }
+    next(vm => {
+      vm.didWarn = missPropWarn
+    })
+  },
+  beforeRouteLeave (to, from, next) {
+    // restore vue config
+    Vue.config.silent = originalSilent
+    Vue.config.warnHandler = originalWarnHandler
+    next()
+  }
+}
 
 const router = new VueRouter({
   mode: 'history',
@@ -80,6 +125,24 @@ const router = new VueRouter({
           ]
         }
       ]
+    },
+    {
+      path: '/config-required-props',
+      component: Parent,
+      props: { msg: 'from parent' },
+      children: [
+        {
+          path: 'child',
+          component: RequiredProps,
+          props: {
+            msg: 'from child'
+          }
+        }
+      ]
+    },
+    {
+      path: '/catch-warn',
+      component: CatchWarn
     }
   ]
 })
@@ -96,6 +159,9 @@ new Vue({
         <li><router-link to="/with-guard2">/with-guard2</router-link></li>
         <li><router-link to="/one/two/child1">/one/two/child1</router-link></li>
         <li><router-link to="/one/two/child2">/one/two/child2</router-link></li>
+        <li><router-link to="/config-required-props">/config-required-props</router-link></li>
+        <li><router-link to="/config-required-props/child">/config-required-props/child</router-link></li>
+        <li><router-link to="/catch-warn">/catch-warn</router-link></li>
       </ul>
       <keep-alive>
         <router-view class="view"></router-view>

src/components/view.js

@@ -39,17 +39,32 @@ export default {
 
     // render previous view if the tree is inactive and kept-alive
     if (inactive) {
-      return h(cache[name], data, children)
+      const cachedData = cache[name]
+      const cachedComponent = cachedData && cachedData.component
+      if (cachedComponent) {
+        // #2301
+        // pass props
+        if (cachedData.configProps) {
+          fillPropsinData(cachedComponent, data, cachedData.route, cachedData.configProps)
+        }
+        return h(cachedComponent, data, children)
+      } else {
+        // render previous empty view
+        return h()
+      }
     }
 
     const matched = route.matched[depth]
-    // render empty node if no matched route
-    if (!matched) {
+    const component = matched && matched.components[name]
+
+    // render empty node if no matched route or no config component
+    if (!matched || !component) {
       cache[name] = null
       return h()
     }
 
-    const component = cache[name] = matched.components[name]
+    // cache component
+    cache[name] = { component }
 
     // attach instance registration hook
     // this will be called in the instance's injected lifecycle hooks
@@ -81,25 +96,37 @@ export default {
       }
     }
 
-    // resolve props
-    let propsToPass = data.props = resolveProps(route, matched.props && matched.props[name])
-    if (propsToPass) {
-      // clone to prevent mutation
-      propsToPass = data.props = extend({}, propsToPass)
-      // pass non-declared props as attrs
-      const attrs = data.attrs = data.attrs || {}
-      for (const key in propsToPass) {
-        if (!component.props || !(key in component.props)) {
-          attrs[key] = propsToPass[key]
-          delete propsToPass[key]
-        }
-      }
+    const configProps = matched.props && matched.props[name]
+    // save route and configProps in cachce
+    if (configProps) {
+      extend(cache[name], {
+        route,
+        configProps
+      })
+      fillPropsinData(component, data, route, configProps)
     }
 
     return h(component, data, children)
   }
 }
 
+function fillPropsinData (component, data, route, configProps) {
+  // resolve props
+  let propsToPass = data.props = resolveProps(route, configProps)
+  if (propsToPass) {
+    // clone to prevent mutation
+    propsToPass = data.props = extend({}, propsToPass)
+    // pass non-declared props as attrs
+    const attrs = data.attrs = data.attrs || {}
+    for (const key in propsToPass) {
+      if (!component.props || !(key in component.props)) {
+        attrs[key] = propsToPass[key]
+        delete propsToPass[key]
+      }
+    }
+  }
+}
+
 function resolveProps (route, config) {
   switch (typeof config) {
     case 'undefined':

test/e2e/specs/keepalive-view.js

@@ -9,7 +9,7 @@ module.exports = {
     browser
       .url('http://localhost:8080/keepalive-view/')
       .waitForElementVisible('#app', 1000)
-      .assert.count('li a', 7)
+      .assert.count('li a', 10)
 
       .click('li:nth-child(1) a')
       .assert.containsText('.view', 'index child1')
@@ -44,6 +44,17 @@ module.exports = {
       .click('li:nth-child(7) a')
       .assert.containsText('.view', 'index child2')
 
+      // missing props in nested routes with keep alive
+      // https://github.com/vuejs/vue-router/issues/2301
+      .click('li:nth-child(8) a')
+      .assert.containsText('.view', 'msg: from parent')
+      .click('li:nth-child(9) a')
+      .assert.containsText('.view', 'msg: from parent\nprops from route config is: from child')
+      .click('li:nth-child(10) a')
+      .assert.containsText('.view', 'no missing prop warn')
+      .click('li:nth-child(9) a')
+      .assert.containsText('.view', 'msg: from parent\nprops from route config is: from child')
+
       .end()
   }
 }