Digitransit-ui is a React based web application. The following bullet point describe the architecture on a overview level and provide guidelines on how the code should be.
- Front-end is written using modern javascript (ES2015)
- Use Babel to transpile into ES5
- We could provide a different bundle for modern browsers using widely-supported es6 syntax
- Use polyfills for older browsers by polyfill-service
- React + JSX
- Airbnb styleguide for ES6 and React
- Use object property spread instead of Object.assign when creating new objects: not Object.assign({}, {state}, {a: 1, b: 2}), but instead {...state, a:1, b: 2}
- Three types of components
- Views
- Simple views that transform props to JSX
- Views must contain only dom elements and other Views
- i.e. no no references to containers
- Views should preferably be created using stateless functional components
- Views mustn't hold any state
- If state is needed you should either store it using fluxible or in a container
- Must be included in the style guide
- Visual regression testing using gemini
- all use cases should be provided by the style guide
- RelayConnector
- Data from server should be fetched by adding a relay fragment and wrapping it with Relay.createContainer
- The file should have the pure view as default export and the RelayConnector as named export
- Alternatively both components can be placed in separate files
- The view should use RelayContainers in its render method if props.relay is defined. If props.relay is not defined, then the pure view should be used instead.
- Containers
- Two types of containers
- "Traditional" containers
- Containers are components that do complex transformations of props data in order to show one or more views or containers
- Containers should only contain only other containers and views
- i.e. no dom components
- Continers must include Container in their name
- StoreConnectors
- Data from stores should be loaded using fluxible connectToStores
- Higher order component that wraps another component to provide store state to other component props
- Must include StoreConnector in their name
- Containers should include unit tests either testing their functions separately or by testing it's shallow rendering using Enzyme
- Most commonly used flows, i.e. making a route search and navigating routes/stops/trips should be tested using Nightwatch
- Should be tested in browserstack using most commonly used browsers
- Incremental process
- When working with a file
- add to style guide
- write gemini and/or unit tests
- create gemini images
React components can access data in two different ways:
- Open Trip Planner GraphQL queries with Relay
- Other querys with Flux model
Basically, division between alternatives is:
- GraphQL is used to fetch data from server
- If server endpoint does not support GraphQL, flux can be used to retrieve that data
- Flux stores are mainly used to store application state
Links:
- https://facebook.github.io/flux/docs/overview.html
- http://facebook.github.io/react/
- https://github.com/rackt/react-router
- https://facebook.github.io/relay/
- https://facebook.github.io/graphql/
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Modular CSS
- how to implement is still a good question
- Prefer fluxbox based layouts if it simplifies the layouting process
- We should provide information about layout (mobile/tablet/desktop) in the context by using matchMedia or browser sniffing in order for the containers to be able to render different contents depending on the device
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How to get there
- Still a uncertain process