Merge branch 'master' into collapsable-pipeline-settingscollapsable-pipeline-settings

* master: (260 commits)
  Enable auto-retry in GitLab CI/CD pipeline
  Clean up new navigation templates
  Wait for gitaly to boot during tests
  Update 'Visibility of pipelines'
  refactored code
  Fix note resolution specs
  Add author and MR to changelog
  Tidy up projects API specs
  Resolve outdated diff discussions on push
  Fix migration
  change collapse to resolve and comments to discussions
  add unit tests for new collapse_outdated_diff_comments toggle
  Add functionality to collapse outdated diff comments regardless of discussion resolution
  refactor code based on feedback
  fix spec failures
  Use flexbox for prometheus graph row grouping instead of bootstrap classes
  Fix wrong API status codes
  small refactor
  Hide admin link from default search results for non-admins
  Make search dropdowns consistent
  ...

1 files changed, 288 insertions, 3 deletions

diff --git a/doc/development/fe_guide/vue.md b/doc/development/fe_guide/vue.md
index 0742b202807..2607353782a 100644
--- a/doc/development/fe_guide/vue.md
+++ b/doc/development/fe_guide/vue.md
@@ -28,8 +28,9 @@ As always, the Frontend Architectural Experts are available to help with any Vue
 
 All new features built with Vue.js must follow a [Flux architecture][flux].
 The main goal we are trying to achieve is to have only one data flow and only one data entry.
-In order to achieve this goal, each Vue bundle needs a Store - where we keep all the data -,
-a Service - that we use to communicate with the server - and a main Vue component.
+In order to achieve this goal, you can either use [vuex](#vuex) or use the [store pattern][state-management], explained below:
+
+Each Vue bundle needs a Store - where we keep all the data -,a Service - that we use to communicate with the server - and a main Vue component.
 
 Think of the Main Vue Component as the entry point of your application. This is the only smart
 component that should exist in each Vue feature.
@@ -74,6 +75,59 @@ provided as a prop to the main component.
 
 Don't forget to follow [these steps.][page_specific_javascript]
 
+### Bootstrapping Gotchas
+#### Providing data from Haml to JavaScript
+While mounting a Vue application may be a need to provide data from Rails to JavaScript.
+To do that, provide the data through `data` attributes in the HTML element and query them while mounting the application.
+
+_Note:_ You should only do this while initing the application, because the mounted element will be replaced with Vue-generated DOM.
+
+The advantage of providing data from the DOM to the Vue instance through `props` in the `render` function
+instead of querying the DOM inside the main vue component is that makes tests easier by avoiding the need to
+create a fixture or an HTML element in the unit test. See the following example:
+
+```javascript
+// haml
+.js-vue-app{ data: { endpoint: 'foo' }}
+
+document.addEventListener('DOMContentLoaded', () => new Vue({
+  el: '.js-vue-app',
+  data() {
+    const dataset = this.$options.el.dataset;
+    return {
+      endpoint: dataset.endpoint,
+    };
+  },
+  render(createElement) {
+    return createElement('my-component', {
+      props: {
+        endpoint: this.isLoading,
+      },
+    });
+  },
+}));
+```
+
+#### Accessing the `gl` object
+When we need to query the `gl` object for data that won't change during the application's lyfecyle, we should do it in the same place where we query the DOM.
+By following this practice, we can avoid the need to mock the `gl` object, which will make tests easier.
+It should be done while initializing our Vue instance, and the data should be provided as `props` to the main component:
+
+##### example:
+```javascript
+
+document.addEventListener('DOMContentLoaded', () => new Vue({
+  el: '.js-vue-app',
+  render(createElement) {
+    return createElement('my-component', {
+      props: {
+        username: gon.current_username,
+      },
+    });
+  },
+}));
+```
+
 ### A folder for Components
 
 This folder holds all components that are specific of this new feature.
@@ -89,6 +143,29 @@ in one table would not be a good use of this pattern.
 
 You can read more about components in Vue.js site, [Component System][component-system]
 
+#### Components Gotchas
+1. Using SVGs in components: To use an SVG in a template we need to make it a property we can access through the component.
+A `prop` and a property returned by the `data` functions require `vue` to set a `getter` and a `setter` for each of them.
+The SVG should be a computed property in order to improve performance, note that computed properties are cached based on their dependencies.
+
+```javascript
+// bad
+import svg from 'svg.svg';
+data() {
+  return {
+    myIcon: svg,
+  };
+};
+
+// good
+import svg from 'svg.svg';
+computed: {
+  myIcon() {
+    return svg;
+  }
+}
+```
+
 ### A folder for the Store
 
 The Store is a class that allows us to manage the state in a single
@@ -430,11 +507,23 @@ describe('Todos App', () => {
   });
 });
 ```
+#### `mountComponent` helper
+There is an helper in `spec/javascripts/helpers/vue_mount_component_helper.js` that allows you to mount a component with the given props:
+
+```javascript
+import Vue from 'vue';
+import mountComponent from 'helpers/vue_mount_component_helper.js'
+import component from 'component.vue'
+
+const Component = Vue.extend(component);
+const data = {prop: 'foo'};
+const vm = mountComponent(Component, data);
+```
+
 #### Test the component's output
 The main return value of a Vue component is the rendered output. In order to test the component we
 need to test the rendered output. [Vue][vue-test] guide's to unit test show us exactly that:
 
-
 ### Stubbing API responses
 [Vue Resource Interceptors][vue-resource-interceptor] allow us to add a interceptor with
 the response we need:
@@ -481,6 +570,198 @@ new Component({
 new Component().$mount();
 ```
 
+## Vuex
+To manage the state of an application you may use [Vuex][vuex-docs].
+
+_Note:_ All of the below is explained in more detail in the official [Vuex documentation][vuex-docs].
+
+### Separation of concerns
+Vuex is composed of State, Getters, Mutations, Actions and Modules.
+
+When a user clicks on an action, we need to `dispatch` it. This action will `commit` a mutation that will change the state.
+_Note:_ The action itself will not update the state, only a mutation should update the state.
+
+#### File structure
+When using Vuex at GitLab, separate this concerns into different files to improve readability. If you can, separate the Mutation Types as well:
+
+```
+└── store
+  ├── index.js          # where we assemble modules and export the store
+  ├── actions.js        # actions
+  ├── mutations.js      # mutations
+  ├── getters.js        # getters
+  └── mutation_types.js # mutation types
+```
+The following examples show an application that lists and adds users to the state.
+
+##### `index.js`
+This is the entry point for our store. You can use the following as a guide:
+
+```javascript
+import Vue from 'vue';
+import Vuex from 'vuex';
+import * as actions from './actions';
+import * as mutations from './mutations';
+
+Vue.use(Vuex);
+
+export default new Vuex.Store({
+  actions,
+  getters,
+  state: {
+    users: [],
+  },
+});
+```
+_Note:_ If the state of the application is too complex, an individual file for the state may be better.
+
+#### `actions.js`
+An action commits a mutatation. In this file, we will write the actions that will call the respective mutation:
+
+```javascript
+  import * as types from './mutation-types'
+
+  export const addUser = ({ commit }, user) => {
+    commit(types.ADD_USER, user);
+  };
+```
+
+To dispatch an action from a component, use the `mapActions` helper:
+```javascript
+import { mapActions } from 'vuex';
+
+{
+  methods: {
+    ...mapActions([
+      'addUser',
+    ]),
+    onClickUser(user) {
+      this.addUser(user);
+    },
+  },
+};
+```
+
+#### `getters.js`
+Sometimes we may need to get derived state based on store state, like filtering for a specific prop. This can be done through the `getters`:
+
+```javascript
+// get all the users with pets
+export getUsersWithPets = (state, getters) => {
+  return state.users.filter(user => user.pet !== undefined);
+};
+```
+
+To access a getter from a component, use the `mapGetters` helper:
+```javascript
+import { mapGetters } from 'vuex';
+
+{
+  computed: {
+    ...mapGetters([
+      'getUsersWithPets',
+    ]),
+  },
+};
+```
+
+#### `mutations.js`
+The only way to actually change state in a Vuex store is by committing a mutation.
+
+```javascript
+  import * as types from './mutation-types'
+  export default {
+    [types.ADD_USER](state, user) {
+      state.users.push(user);
+    },
+  };
+```
+
+#### `mutations_types.js`
+From [vuex mutations docs][vuex-mutations]:
+> It is a commonly seen pattern to use constants for mutation types in various Flux implementations. This allows the code to take advantage of tooling like linters, and putting all constants in a single file allows your collaborators to get an at-a-glance view of what mutations are possible in the entire application.
+
+```javascript
+export const ADD_USER = 'ADD_USER';
+```
+
+### How to include the store in your application
+The store should be included in the main component of your application:
+```javascript
+  // app.vue
+  import store from 'store'; // it will include the index.js file
+
+  export default {
+    name: 'application',
+    store,
+    ...
+  };
+```
+
+### Vuex Gotchas
+1. Avoid calling a mutation directly. Always use an action to commit a mutation. Doing so will keep consistency through out the application. From Vuex docs:
+
+  >  why don't we just call store.commit('action') directly? Well, remember that mutations must be synchronous? Actions aren't. We can perform asynchronous operations inside an action.
+
+  ```javascript
+    // component.vue
+
+    // bad
+    created() {
+      this.$store.commit('mutation');
+    }
+
+    // good
+    created() {
+      this.$store.dispatch('action');
+    }
+  ```
+1. When possible, use mutation types instead of hardcoding strings. It will be less error prone.
+1. The State will be accessible in all components descending from the use where the store is instantiated.
+
+### Testing Vuex
+#### Testing Vuex concerns
+Refer to [vuex docs][vuex-testing] regarding testing Actions, Getters and Mutations.
+
+#### Testing components that need a store
+Smaller components might use `store` properties to access the data.
+In order to write unit tests for those components, we need to include the store and provide the correct state:
+
+```javascript
+//component_spec.js
+import Vue from 'vue';
+import store from './store';
+import component from './component.vue'
+
+describe('component', () => {
+  let vm;
+  let Component;
+
+  beforeEach(() => {
+    Component = Vue.extend(issueActions);
+  });
+
+  afterEach(() => {
+    vm.$destroy();
+  });
+
+  it('should show a user', () => {
+    const user = {
+      name: 'Foo',
+      age: '30',
+    };
+
+    // populate the store
+    store.dipatch('addUser', user);
+
+    vm = new Component({
+      store,
+      propsData: props,
+    }).$mount();
+  });
+});
+```
+
 [vue-docs]: http://vuejs.org/guide/index.html
 [issue-boards]: https://gitlab.com/gitlab-org/gitlab-ce/tree/master/app/assets/javascripts/boards
 [environments-table]: https://gitlab.com/gitlab-org/gitlab-ce/tree/master/app/assets/javascripts/environments
@@ -493,3 +774,7 @@ new Component().$mount();
 [vue-test]: https://vuejs.org/v2/guide/unit-testing.html
 [issue-boards-service]: https://gitlab.com/gitlab-org/gitlab-ce/blob/master/app/assets/javascripts/boards/services/board_service.js.es6
 [flux]: https://facebook.github.io/flux
+[vuex-docs]: https://vuex.vuejs.org
+[vuex-structure]: https://vuex.vuejs.org/en/structure.html
+[vuex-mutations]: https://vuex.vuejs.org/en/mutations.html
+[vuex-testing]: https://vuex.vuejs.org/en/testing.html