ES6のmodules
javascript - When should I use curly braces for ES6 import? - Stack Overflow
16. Modules
ES6 modules are stored in files. There is exactly one module per file and one file per module. You have two ways of exporting things from a module. These two ways can be mixed, but it is usually better to use them separately.
Read Understanding ECMAScript 6 | Leanpub
via
https://facebook.github.io/create-react-app/docs/importing-a-component
#JavaScriptのmodules