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diff --git a/doc/development/fe_guide/vue.md b/doc/development/fe_guide/vue.md index 3e3406e7d6a..a984bb6c94c 100644 --- a/doc/development/fe_guide/vue.md +++ b/doc/development/fe_guide/vue.md @@ -19,13 +19,31 @@ We don't want to refactor all GitLab frontend code into Vue.js, here are some gu when not to use Vue.js: - Adding or changing static information; -- Features that highly depend on jQuery will be hard to work with Vue.js +- Features that highly depend on jQuery will be hard to work with Vue.js; +- Features without reactive data; As always, the Frontend Architectural Experts are available to help with any Vue or JavaScript questions. -## How to build a new feature with Vue.js +## Vue architecture -**Components, Stores and Services** +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. + +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. +This component is responsible for: +1. Calling the Service to get data from the server +1. Calling the Store to store the data received +1. Mounting all the other components + +  + +You can also read about this architecture in vue docs about [state management][state-management] +and about [one way data flow][one-way-data-flow]. + +### Components, Stores and Services In some features implemented with Vue.js, like the [issue board][issue-boards] or [environments table][environments-table] @@ -46,16 +64,17 @@ _For consistency purposes, we recommend you to follow the same structure._ Let's look into each of them: -**A `*_bundle.js` file** +### A `*_bundle.js` file This is the index file of your new feature. This is where the root Vue instance of the new feature should be. -The Store and the Service should be imported and initialized in this file and provided as a prop to the main component. +The Store and the Service should be imported and initialized in this file and +provided as a prop to the main component. Don't forget to follow [these steps.][page_specific_javascript] -**A folder for Components** +### A folder for Components This folder holds all components that are specific of this new feature. If you need to use or create a component that will probably be used somewhere @@ -70,20 +89,219 @@ 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] -**A folder for the Store** +### A folder for the Store The Store is a class that allows us to manage the state in a single -source of truth. +source of truth. It is not aware of the service or the components. The concept we are trying to follow is better explained by Vue documentation itself, please read this guide: [State Management][state-management] -**A folder for the Service** +### A folder for the Service + +The Service is a class used only to communicate with the server. +It does not store or manipulate any data. It is not aware of the store or the components. +We use [vue-resource][vue-resource-repo] to communicate with the server. + +Vue Resource should only be imported in the service file. + + ```javascript + import Vue from 'vue'; + import VueResource from 'vue-resource'; + + Vue.use(VueResource); + ``` + +### CSRF token +We use a Vue Resource interceptor to manage the CSRF token. +`app/assets/javascripts/vue_shared/vue_resource_interceptor.js` holds all our common interceptors. +Note: You don't need to load `app/assets/javascripts/vue_shared/vue_resource_interceptor.js` +since it's already being loaded by `common_vue.js`. + +### End Result + +The following example shows an application: + +```javascript +// store.js +export default class Store { + + /** + * This is where we will iniatialize the state of our data. + * Usually in a small SPA you don't need any options when starting the store. In the case you do + * need guarantee it's an Object and it's documented. + * + * @param {Object} options + */ + constructor(options) { + this.options = options; + + // Create a state object to handle all our data in the same place + this.todos = []: + } + + setTodos(todos = []) { + this.todos = todos; + } + + addTodo(todo) { + this.todos.push(todo); + } + + removeTodo(todoID) { + const state = this.todos; + + const newState = state.filter((element) => {element.id !== todoID}); + + this.todos = newState; + } +} + +// service.js +import Vue from 'vue'; +import VueResource from 'vue-resource'; +import 'vue_shared/vue_resource_interceptor'; + +Vue.use(VueResource); + +export default class Service { + constructor(options) { + this.todos = Vue.resource(endpoint.todosEndpoint); + } + + getTodos() { + return this.todos.get(); + } + + addTodo(todo) { + return this.todos.put(todo); + } +} +// todo_component.vue +<script> +export default { + props: { + data: { + type: Object, + required: true, + }, + } +} +</script> +<template> + <div> + <h1> + Title: {{data.title}} + </h1> + <p> + {{data.text}} + </p> + </div> +</template> + +// todos_main_component.vue +<script> +import Store from 'store'; +import Service from 'service'; +import TodoComponent from 'todoComponent'; +export default { + /** + * Although most data belongs in the store, each component it's own state. + * We want to show a loading spinner while we are fetching the todos, this state belong + * in the component. + * + * We need to access the store methods through all methods of our component. + * We need to access the state of our store. + */ + data() { + const store = new Store(); + + return { + isLoading: false, + store: store, + todos: store.todos, + }; + }, + + components: { + todo: TodoComponent, + }, + + created() { + this.service = new Service('todos'); + + this.getTodos(); + }, + + methods: { + getTodos() { + this.isLoading = true; + + this.service.getTodos() + .then(response => response.json()) + .then((response) => { + this.store.setTodos(response); + this.isLoading = false; + }) + .catch(() => { + this.isLoading = false; + // Show an error + }); + }, + + addTodo(todo) { + this.service.addTodo(todo) + then(response => response.json()) + .then((response) => { + this.store.addTodo(response); + }) + .catch(() => { + // Show an error + }); + } + } +} +</script> +<template> + <div class="container"> + <div v-if="isLoading"> + <i + class="fa fa-spin fa-spinner" + aria-hidden="true" /> + </div> + + <div + v-if="!isLoading" + class="js-todo-list"> + <template v-for='todo in todos'> + <todo :data="todo" /> + </template> + + <button + @click="addTodo" + class="js-add-todo"> + Add Todo + </button> + </div> + <div> +</template> + +// bundle.js +import todoComponent from 'todos_main_component.vue'; + +new Vue({ + el: '.js-todo-app', + components: { + todoComponent, + }, + render: createElement => createElement('todo-component' { + props: { + someProp: [], + } + }), +}); -The Service is used only to communicate with the server. -It does not store or manipulate any data. -We use [vue-resource][vue-resource-repo] to -communicate with the server. +``` The [issue boards service][issue-boards-service] is a good example of this pattern. @@ -93,6 +311,128 @@ is a good example of this pattern. Please refer to the Vue section of our [style guide](style_guide_js.md#vuejs) for best practices while writing your Vue components and templates. +## Testing Vue Components + +Each Vue component has a unique output. This output is always present in the render function. + +Although we can test each method of a Vue component individually, our goal must be to test the output +of the render/template function, which represents the state at all times. + +Make use of Vue Resource Interceptors to mock data returned by the service. + +Here's how we would test the Todo App above: + +```javascript +import component from 'todos_main_component'; + +describe('Todos App', () => { + it('should render the loading state while the request is being made', () => { + const Component = Vue.extend(component); + + const vm = new Component().$mount(); + + expect(vm.$el.querySelector('i.fa-spin')).toBeDefined(); + }); + + describe('with data', () => { + // Mock the service to return data + const interceptor = (request, next) => { + next(request.respondWith(JSON.stringify([{ + title: 'This is a todo', + body: 'This is the text' + }]), { + status: 200, + })); + }; + + let vm; + + beforeEach(() => { + Vue.http.interceptors.push(interceptor); + + const Component = Vue.extend(component); + + vm = new Component().$mount(); + }); + + afterEach(() => { + Vue.http.interceptors = _.without(Vue.http.interceptors, interceptor); + }); + + + it('should render todos', (done) => { + setTimeout(() => { + expect(vm.$el.querySelectorAll('.js-todo-list div').length).toBe(1); + done(); + }, 0); + }); + }); + + describe('add todo', () => { + let vm; + beforeEach(() => { + const Component = Vue.extend(component); + vm = new Component().$mount(); + }); + it('should add a todos', (done) => { + setTimeout(() => { + vm.$el.querySelector('.js-add-todo').click(); + + // Add a new interceptor to mock the add Todo request + Vue.nextTick(() => { + expect(vm.$el.querySelectorAll('.js-todo-list div').length).toBe(2); + }); + }, 0); + }); + }); +}); +``` +#### Test the component's output +The main return value of a Vue component is the rendered output. In order to test the component we +need to test the rendered output. [Vue][vue-test] guide's to unit test show us exactly that: + + +### Stubbing API responses +[Vue Resource Interceptors][vue-resource-interceptor] allow us to add a interceptor with +the response we need: + +```javascript + // Mock the service to return data + const interceptor = (request, next) => { + next(request.respondWith(JSON.stringify([{ + title: 'This is a todo', + body: 'This is the text' + }]), { + status: 200, + })); + }; + + beforeEach(() => { + Vue.http.interceptors.push(interceptor); + }); + + afterEach(() => { + Vue.http.interceptors = _.without(Vue.http.interceptors, interceptor); + }); + + it('should do something', (done) => { + setTimeout(() => { + // Test received data + done(); + }, 0); + }); +``` + +1. Use `$.mount()` to mount the component +```javascript + // bad + new Component({ + el: document.createElement('div') + }); + + // good + new Component().$mount(); +``` [vue-docs]: http://vuejs.org/guide/index.html [issue-boards]: https://gitlab.com/gitlab-org/gitlab-ce/tree/master/app/assets/javascripts/boards @@ -100,5 +440,9 @@ for best practices while writing your Vue components and templates. [page_specific_javascript]: https://docs.gitlab.com/ce/development/frontend.html#page-specific-javascript [component-system]: https://vuejs.org/v2/guide/#Composing-with-Components [state-management]: https://vuejs.org/v2/guide/state-management.html#Simple-State-Management-from-Scratch +[one-way-data-flow]: https://vuejs.org/v2/guide/components.html#One-Way-Data-Flow [vue-resource-repo]: https://github.com/pagekit/vue-resource +[vue-resource-interceptor]: https://github.com/pagekit/vue-resource/blob/develop/docs/http.md#interceptors +[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 |