Convert week_number.jsx to flow (as a simple example) (Hacker0x01#1307)

* Convert week_number.jsx to flow (as a simple example)

Workaround for react-docgen#125

* Run flow from lint script

.flowconfig

@@ -0,0 +1,11 @@
+[ignore]
+
+[include]
+
+[libs]
+
+[lints]
+
+[options]
+
+[strict]

package.json

@@ -44,6 +44,7 @@
     "eslint-plugin-react": "^7.4.0",
     "express": "^4.16.2",
     "extract-text-webpack-plugin": "^1.0.1",
+    "flow-bin": "^0.68.0",
     "highlight.js": "^9.12.0",
     "husky": "^0.14.3",
     "isparta-loader": "^2.0.0",
@@ -95,10 +96,11 @@
   },
   "scripts": {
     "eslint": "eslint {src,test,docs-site/src}/**/*.{js,jsx} *.js",
+    "flow": "flow",
     "precommit": "lint-staged",
     "sass-lint":
       "sass-lint --config .sass-lint.yml 'src/stylesheets/*.scss, docs-site/src/*.scss' -i 'docs-site/src/higlight.scss, docs-site/src/reset.scss'",
-    "lint": "run-p eslint sass-lint",
+    "lint": "run-p eslint flow sass-lint",
     "start": "cross-env MODULES=false node server.js",
     "test": "cross-env NODE_ENV=test karma start karma.conf.js --single-run",
     "prepublish": "test $(npm -v | tr . '\\n' | head -n 1) -ge '4' || exit 1",

src/week_number.jsx

@@ -1,14 +1,18 @@
+// @flow
 import React from "react";
 import PropTypes from "prop-types";
 import classnames from "classnames";
 
-export default class WeekNumber extends React.Component {
+export default class WeekNumber extends React.Component<{
+  weekNumber: number,
+  onClick?: Function
+}> {
   static propTypes = {
     weekNumber: PropTypes.number.isRequired,
     onClick: PropTypes.func
   };
 
-  handleClick = event => {
+  handleClick = (event: any) => {
     if (this.props.onClick) {
       this.props.onClick(event);
     }

yarn.lock

@@ -2841,6 +2841,10 @@ flatten@^1.0.2:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/flatten/-/flatten-1.0.2.tgz#dae46a9d78fbe25292258cc1e780a41d95c03782"
 
+flow-bin@^0.68.0:
+  version "0.68.0"
+  resolved "https://registry.yarnpkg.com/flow-bin/-/flow-bin-0.68.0.tgz#86c2d14857d306eb2e85e274f2eebf543564f623"
+
 for-in@^1.0.1:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/for-in/-/for-in-1.0.2.tgz#81068d295a8142ec0ac726c6e2200c30fb6d5e80"