Create React App flow stubs

.flowconfig

[options]
module.name_mapper.extension='module.css' -> 'CSSModule'
module.name_mapper.extension='svg' -> 'SVGModule'
module.system=haste

css-module-stub.js

// flow-typed/global/css-module-stub.js
// @flow

type CSSModuleType = { [key: string]: string };

declare module "CSSModule" {
  declare module.exports: CSSModuleType;
}

svg-module-stub.js

// flow-typed/global/svg-module-stub.js
// @flow

// TODO: create props type the right way
type SVGComponentPropsType = {|
  className?: string
|};

type SVGComponentType = (props: SVGComponentPropsType) => React$Element<"svg">;

type SVGModuleType = {
  ReactComponent: SVGComponentType
};

declare module "SVGModule" {
  declare module.exports: SVGModuleType;