Architecture
Diagrams about Cylc UI architecture. Useful for other developers, not intended for wider audience.
The following diagram illustrates the stack used to build Cylc UI. The main library, although not highlighted in the figure, is Vue. Cylc UI is a ES6 Vue application, built with vue-cli. It is easier to read the diagram from the bottom up.
At the bottom of the stack we have the transpiler Babel, which does things like rewriting const nodeId = node.node?.id (null coalescing operator, not supported in browsers) to something like const nodeId = (node.node) ? node.node.id : undefined. It also transpiles code from libraries like Vuetify (see babel.config.js).
webpack is the bundler used by our code. It coordinates babel, sass, postcss, etc., producing the final files of our application.
It is worth opening the GitHub README.md of each of these building tools, if not already familiar with any of them.
In the middle of the diagram we have libraries. At the top of the libraries panel we have Vue libraries such as Vue, VueRouter (navigation), Vuex (UI data store), and Vuetify (UI framework). These are closely related to Vue. Next we have utility libraries such as lodash (utilities not found in the JS language), graphql (parsing & merging queries), enumify (because ES6 doesn't have enums), and @mdi/js (material design icons for JS). The penultimate row from the top has just mitt (event bus) and Lumino (tabbed layout). Finally, we have the two libraries used for communication. Axios is used for REST (e.g. JupyterHub REST API) and ApolloClient is used for GraphQL (e.g. GraphiQL, mutations, subscriptions.)
This diagram shows an example of how the UI components are organized when you access the route /#/ (the application dashboard) in your browser. Take a look at src/router/index.js to see what else VueRouter is doing. And for the layout, look at the App.vue computed variables.
The VMain component is not in our source code directory. It was left intentionally to show that Alert.vue and Dashboard.vue both share a parent, and also to point that we have several components in the UI structure that are imported from Vuetify.
The best way to visualize the complete list of components and how they are organized hierarchically is using the Vue Dev Utils browser extension. Note in the Vue Dev Utils screenshot below that it displays the same structure above, but with more components.
NOTE: there are two Vue extensions in the screenshot above, one for Vue 2 and one for Vue 3. Pay attention to which version you install. Cylc UI is built with Vue 2.