diff --git a/.circleci/config.yml b/.circleci/config.yml
index cff98bd..4290be4 100755
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -76,7 +76,7 @@ jobs:
       - attach-project
       - run:
           name: E2E SSR Tests
-          command: yarn build && yarn test:e2e-ssr
+          command: yarn build && yarn test:e2e-ssr --coverage && yarn coverage
       - persist_to_workspace:
           root: ~/project
           paths:
diff --git a/src/client/updaters/attribute.js b/src/client/updaters/attribute.js
index 19fa3b4..c4b14cb 100644
--- a/src/client/updaters/attribute.js
+++ b/src/client/updaters/attribute.js
@@ -43,8 +43,6 @@ export default function updateAttribute (appId, { attribute } = {}, type, attrs,
       if (attrs[attr]) {
         data[attr] = data[attr] || {}
         data[attr][appId] = attrs[attr]
-      } else {
-        delete data[attr][appId]
       }
     }
   }
diff --git a/src/index.js b/src/index.js
index 14c3393..16528d8 100644
--- a/src/index.js
+++ b/src/index.js
@@ -28,6 +28,6 @@ function install (Vue, options = {}) {
 export default {
   version,
   install,
-  generate: process.server ? generate : () => showWarningNotSupportedInBrowserBundle('generate'),
+  generate: metaInfo => process.server ? generate(metaInfo) : showWarningNotSupportedInBrowserBundle('generate'),
   hasMetaInfo
 }
diff --git a/src/server/generateServerInjector.js b/src/server/generateServerInjector.js
index 43368ff..a00818d 100644
--- a/src/server/generateServerInjector.js
+++ b/src/server/generateServerInjector.js
@@ -58,13 +58,15 @@ export default function generateServerInjector (options, metaInfo) {
             }
           }
 
-          for (const appId in serverInjector.extraData) {
-            const data = serverInjector.extraData[appId][type]
-            if (data) {
-              for (const attr in data) {
-                attributeData[attr] = {
-                  ...attributeData[attr],
-                  [appId]: data[attr]
+          if (serverInjector.extraData) {
+            for (const appId in serverInjector.extraData) {
+              const data = serverInjector.extraData[appId][type]
+              if (data) {
+                for (const attr in data) {
+                  attributeData[attr] = {
+                    ...attributeData[attr],
+                    [appId]: data[attr]
+                  }
                 }
               }
             }
diff --git a/src/shared/mixin.js b/src/shared/mixin.js
index cf75ea0..fd2ec17 100644
--- a/src/shared/mixin.js
+++ b/src/shared/mixin.js
@@ -155,6 +155,7 @@ export default function createMixin (Vue, options) {
       // Wait that element is hidden before refreshing meta tags (to support animations)
       const interval = setInterval(() => {
         if (this.$el && this.$el.offsetParent !== null) {
+          /* istanbul ignore next line */
           return
         }
 
diff --git a/test/components/hello-world.vue b/test/components/hello-world.vue
index 9b3721c..88bc599 100644
--- a/test/components/hello-world.vue
+++ b/test/components/hello-world.vue
@@ -6,12 +6,7 @@
 export default {
   metaInfo() {
     return {
-      title: this.title
-    }
-  },
-  data() {
-    return {
-      title: 'Hello World',
+      title: this.title,
       htmlAttrs: {
         lang: 'en'
       },
@@ -19,6 +14,11 @@ export default {
         { charset: 'utf-8' }
       ]
     }
+  },
+  data() {
+    return {
+      title: 'Hello World',
+    }
   }
 }
 </script>
diff --git a/test/unit/components.test.js b/test/unit/components.test.js
index aa49fee..d155ba6 100644
--- a/test/unit/components.test.js
+++ b/test/unit/components.test.js
@@ -14,9 +14,9 @@ jest.mock('../../src/utils/window', () => ({
   hasGlobalWindow: false
 }))
 
-describe('client', () => {
+describe('components', () => {
   let Vue
-  let html
+  let elements
 
   beforeAll(() => {
     Vue = loadVueMetaPlugin()
@@ -25,15 +25,36 @@ describe('client', () => {
     delete window.requestAnimationFrame
     delete window.cancelAnimationFrame
 
-    html = document.createElement('html')
+    elements = {
+      html: document.createElement('html'),
+      head: document.createElement('head'),
+      body: document.createElement('body')
+    }
+
+    elements.html.appendChild(elements.head)
+    elements.html.appendChild(elements.body)
+
     document._getElementsByTagName = document.getElementsByTagName
     jest.spyOn(document, 'getElementsByTagName').mockImplementation((tag) => {
-      if (tag === 'html') {
-        return [html]
+      if (elements[tag]) {
+        return [elements[tag]]
       }
 
       return document._getElementsByTagName(tag)
     })
+    jest.spyOn(document, 'querySelectorAll').mockImplementation((query) => {
+      return elements.html.querySelectorAll(query)
+    })
+  })
+
+  afterEach(() => {
+    elements.html.getAttributeNames().forEach(name => elements.html.removeAttribute(name))
+    elements.head.childNodes.forEach(child => child.remove())
+    elements.head.getAttributeNames().forEach(name => elements.head.removeAttribute(name))
+    elements.body.childNodes.forEach(child => child.remove())
+    elements.body.getAttributeNames().forEach(name => elements.body.removeAttribute(name))
+
+    clearClientAttributeMap()
   })
 
   test('meta-info refreshed on component\'s data change', () => {
@@ -94,6 +115,22 @@ describe('client', () => {
     expect(metaInfo.title).toEqual(undefined)
   })
 
+  test('warns when component doesnt has metaInfo', () => {
+    const warn = jest.spyOn(console, 'warn').mockImplementation(() => {})
+    const metaInfo = HelloWorld.metaInfo
+    delete HelloWorld.metaInfo
+
+    const wrapper = mount(HelloWorld, { localVue: Vue })
+    wrapper.vm.$meta().inject()
+
+    HelloWorld.metaInfo = metaInfo
+
+    expect(warn).toHaveBeenCalledTimes(1)
+    expect(warn).toHaveBeenCalledWith('This vue app/component has no vue-meta configuration')
+
+    warn.mockRestore()
+  })
+
   test('meta-info can be rendered with inject', () => {
     const wrapper = mount(HelloWorld, { localVue: Vue })
 
@@ -101,8 +138,54 @@ describe('client', () => {
     expect(metaInfo.title.text()).toEqual('<title>Hello World</title>')
   })
 
+  test('inject also renders additional app info', () => {
+    HelloWorld.created = function () {
+      const { set } = this.$meta().addApp('inject-test-app')
+      set({
+        htmlAttrs: { lang: 'nl' },
+        meta: [{ name: 'description', content: 'test-description' }]
+      })
+    }
+
+    const wrapper = mount(HelloWorld, { localVue: Vue })
+
+    const metaInfo = wrapper.vm.$meta().inject()
+    expect(metaInfo.title.text()).toEqual('<title>Hello World</title>')
+
+    expect(metaInfo.htmlAttrs.text()).toEqual('lang="en nl" data-vue-meta="%7B%22lang%22:%7B%22ssr%22:%22en%22,%22inject-test-app%22:%22nl%22%7D%7D"')
+    expect(metaInfo.meta.text()).toEqual('<meta data-vue-meta="ssr" charset="utf-8"><meta data-vue-meta="inject-test-app" name="description" content="test-description">')
+
+    delete HelloWorld.created
+  })
+
+  test('attributes with special meaning or functioning correct with inject', () => {
+    HelloWorld.created = function () {
+      const { set } = this.$meta().addApp('inject-test-app')
+      set({
+        meta: [{ skip: true, name: 'description', content: 'test-description' }],
+        script: [{
+          once: true,
+          callback: true,
+          async: false,
+          json: {
+            a: 1
+          }
+        }]
+      })
+    }
+
+    const wrapper = mount(HelloWorld, { localVue: Vue })
+
+    const metaInfo = wrapper.vm.$meta().inject()
+
+    expect(metaInfo.meta.text()).toEqual('<meta data-vue-meta="ssr" charset="utf-8">')
+    expect(metaInfo.script.text()).toEqual('<script onload="this.__vm_l=1">{"a":1}</script>')
+
+    delete HelloWorld.created
+  })
+
   test('doesnt update when ssr attribute is set', () => {
-    html.setAttribute(defaultOptions.ssrAttribute, 'true')
+    elements.html.setAttribute(defaultOptions.ssrAttribute, 'true')
 
     const el = document.createElement('div')
     el.setAttribute('id', 'app')
@@ -216,6 +299,7 @@ describe('client', () => {
   })
 
   test('changes before hydration initialization trigger an update', async () => {
+    const { html } = elements
     html.setAttribute(defaultOptions.ssrAttribute, 'true')
 
     const el = document.createElement('div')
@@ -257,14 +341,11 @@ describe('client', () => {
     jest.runAllTimers()
 
     expect(html.getAttribute('theme')).toBe('dark')
-    html.removeAttribute('theme')
-
     wrapper.destroy()
   })
 
   test('changes during hydration initialization trigger an update', async () => {
-    clearClientAttributeMap()
-
+    const { html } = elements
     html.setAttribute(defaultOptions.ssrAttribute, 'true')
 
     const el = document.createElement('div')
@@ -304,8 +385,122 @@ describe('client', () => {
     jest.runAllTimers()
 
     expect(html.getAttribute('theme')).toBe('dark')
-    html.removeAttribute('theme')
+    wrapper.destroy()
+  })
+
+  test('can add/remove meta info from additional app ', () => {
+    const { html } = elements
+    let app
+
+    HelloWorld.created = function () {
+      // make sure that app's which set data but are removed before mounting
+      // are really removed
+      const { set, remove } = this.$meta().addApp('my-bogus-app')
+      set({
+        meta: [{ name: 'og:description', content: 'test-description' }]
+      })
+      remove()
+
+      app = this.$meta().addApp('my-test-app')
+      app.set({
+        htmlAttrs: { lang: 'nl' },
+        meta: [{ name: 'description', content: 'test-description' }],
+        script: [{ innerHTML: 'var test = true;' }]
+      })
+    }
+
+    const wrapper = mount(HelloWorld, {
+      localVue: Vue
+    })
+
+    wrapper.vm.$meta().refresh()
+
+    expect(html.getAttribute('lang')).toEqual('en nl')
+    expect(Array.from(html.querySelectorAll('meta')).length).toBe(2)
+    expect(Array.from(html.querySelectorAll('script')).length).toBe(1)
+    expect(Array.from(html.querySelectorAll('[data-vue-meta="my-test-app"]')).length).toBe(2)
+
+    app.remove()
+
+    // add another app to make sure on client data is immediately added
+    const anotherApp = wrapper.vm.$meta().addApp('another-test-app')
+    anotherApp.set({
+      meta: [{ name: 'og:description', content: 'test-description' }]
+    })
+
+    expect(html.getAttribute('lang')).toEqual('en')
+    expect(Array.from(html.querySelectorAll('meta')).length).toBe(2)
+    expect(Array.from(html.querySelectorAll('script')).length).toBe(0)
+    expect(Array.from(html.querySelectorAll('[data-vue-meta="my-test-app"]')).length).toBe(0)
+    expect(Array.from(html.querySelectorAll('[data-vue-meta="another-test-app"]')).length).toBe(1)
+
+    wrapper.destroy()
+    delete HelloWorld.created
+  })
+
+  test('retrieves ssr app config from attribute', () => {
+    const { html, body } = elements
+    html.setAttribute(defaultOptions.ssrAttribute, 'true')
+
+    body.setAttribute('foo', 'bar')
+    body.setAttribute('data-vue-meta', '%7B%22foo%22:%7B%22ssr%22:%22bar%22%7D%7D')
+
+    const el = document.createElement('div')
+    el.setAttribute('id', 'app')
+    el.setAttribute('data-server-rendered', true)
+    document.body.appendChild(el)
+
+    const Component = Vue.extend({
+      metaInfo: {
+        title: 'Test',
+        bodyAttrs: {
+          foo: 'bar'
+        }
+      },
+      render: h => h('div', null, 'Test')
+    })
+
+    const vm = new Component().$mount(el)
+
+    const wrapper = createWrapper(vm)
+
+    wrapper.vm.$meta().refresh()
+    expect(body.getAttribute('foo')).toBe('bar')
+    expect(body.getAttribute('data-vue-meta')).toBe('%7B%22foo%22:%7B%22ssr%22:%22bar%22%7D%7D')
+
+    wrapper.vm.$meta().refresh()
+    expect(body.getAttribute('foo')).toBe('bar')
+    expect(body.getAttribute('data-vue-meta')).toBeNull()
+
+    wrapper.vm.$meta().refresh()
+    expect(body.getAttribute('foo')).toBe('bar')
+    expect(body.getAttribute('data-vue-meta')).toBeNull()
 
     wrapper.destroy()
   })
+
+  test('can toggle refreshOnceOnNavigation runtime', () => {
+    const guards = {}
+    const wrapper = mount(HelloWorld, {
+      localVue: Vue,
+      mocks: {
+        $router: {
+          beforeEach (fn) {
+            guards.before = fn
+          },
+          afterEach (fn) {
+            guards.after = fn
+          }
+        }
+      }
+    })
+
+    expect(guards.before).toBeUndefined()
+    expect(guards.after).toBeUndefined()
+
+    wrapper.vm.$meta().setOptions({ refreshOnceOnNavigation: true })
+
+    expect(guards.before).not.toBeUndefined()
+    expect(guards.after).not.toBeUndefined()
+  })
 })
diff --git a/test/unit/generators.test.js b/test/unit/generators.test.js
index cd4d4f9..84de215 100644
--- a/test/unit/generators.test.js
+++ b/test/unit/generators.test.js
@@ -61,7 +61,7 @@ describe('generators', () => {
   }
 })
 
-describe('extra tests', () => {
+describe.only('extra tests', () => {
   test('empty config doesnt generate a tag', () => {
     const { meta } = generateServerInjector({ meta: [] })
 
@@ -109,4 +109,33 @@ describe('extra tests', () => {
     expect(scriptTags.text({ body: true })).toBe('<script data-vue-meta="ssr" src="/script.js" data-body="true"></script>')
     expect(scriptTags.text({ pbody: true })).toBe('')
   })
+
+  test('add additional app and test head/body injector helpers', () => {
+    const baseInfo = {
+      title: 'hello',
+      htmlAttrs: { lang: 'en' },
+      bodyAttrs: { class: 'base-class' },
+      script: [{ src: '/script.js', body: true }]
+    }
+    const extraInfo = {
+      bodyAttrs: { class: 'extra-class' },
+      script: [{ src: '/script.js', pbody: true }]
+    }
+
+    const serverInjector = _generateServerInjector(defaultOptions, baseInfo)
+    serverInjector.addInfo('test-app', extraInfo)
+
+    const meta = serverInjector.injectors
+
+    expect(meta.script.text()).toBe('')
+    expect(meta.script.text({ body: true })).toBe('<script data-vue-meta="ssr" src="/script.js" data-body="true"></script>')
+    expect(meta.script.text({ pbody: true })).toBe('<script data-vue-meta="test-app" src="/script.js" data-pbody="true"></script>')
+
+    expect(meta.head(true)).toBe('<title>hello</title>\n')
+    expect(meta.bodyPrepend(true)).toBe('<script data-vue-meta="test-app" src="/script.js" data-pbody="true"></script>\n')
+    expect(meta.bodyAppend()).toBe('<script data-vue-meta="ssr" src="/script.js" data-body="true"></script>')
+
+    expect(meta.htmlAttrs.text()).toBe('lang="en" data-vue-meta="%7B%22lang%22:%7B%22ssr%22:%22en%22%7D%7D"')
+    expect(meta.bodyAttrs.text()).toBe('class="base-class extra-class" data-vue-meta="%7B%22class%22:%7B%22ssr%22:%22base-class%22,%22test-app%22:%22extra-class%22%7D%7D"')
+  })
 })
diff --git a/test/unit/plugin.test.js b/test/unit/plugin.test.js
index ba519b5..65a143d 100644
--- a/test/unit/plugin.test.js
+++ b/test/unit/plugin.test.js
@@ -120,6 +120,7 @@ describe('plugin', () => {
   })
 
   test('can use generate export', () => {
+    process.server = true
     const rawInfo = {
       meta: [{ charset: 'utf-8' }]
     }
@@ -131,6 +132,22 @@ describe('plugin', () => {
     expect(metaInfo.script.text()).toBe('')
   })
 
+  test('warning when calling generate in browser build', () => {
+    process.server = false
+    const warn = jest.spyOn(console, 'warn').mockImplementation(() => {})
+
+    const rawInfo = {
+      meta: [{ charset: 'utf-8' }]
+    }
+
+    const metaInfo = VueMetaPlugin.generate(rawInfo)
+    expect(metaInfo).toBeUndefined()
+    expect(warn).toHaveBeenCalledTimes(1)
+    expect(warn).toHaveBeenCalledWith('generate is not supported in browser builds')
+
+    warn.mockRestore()
+  })
+
   test('updates can be paused and resumed', async () => {
     const { batchUpdate: _batchUpdate } = jest.requireActual('../../src/client/update')
     const batchUpdateSpy = batchUpdate.mockImplementation(_batchUpdate)
diff --git a/test/utils/index.js b/test/utils/index.js
index d6d58a4..d0449e2 100644
--- a/test/utils/index.js
+++ b/test/utils/index.js
@@ -1,6 +1,6 @@
 import { JSDOM } from 'jsdom'
 import { mount, shallowMount, createWrapper, createLocalVue } from '@vue/test-utils'
-import { renderToString } from '@vue/server-test-utils'
+import { render, renderToString } from '@vue/server-test-utils'
 import { attributeMap } from '../../src/client/updaters/attribute'
 import { defaultOptions } from '../../src/shared/constants'
 import VueMetaPlugin from '../../src'
@@ -9,8 +9,10 @@ export {
   mount,
   shallowMount,
   createWrapper,
+  render,
   renderToString,
-  VueMetaPlugin
+  VueMetaPlugin,
+  attributeMap
 }
 
 export function getVue () {