React Express

2.1ES2015...
2.3JSX
6.2Redux...
6.3GraphQL...
Class Instance Properties
Class Instance Properties
Class instance properties are a convenient way to declare properties for each instance, equivalent to assigning these properties in the constructor function.
Note that this language feature is currently in the proposal stage (not officially adopted as part of the language yet). It's a "stage 2" proposal, meaning it's unlikely to change. Read more about this here.