Add Flowtype (WIP) (#530)

* Add 'flowtype' checking to 'node_package' folder
* Enable flowtype for Authenticity.js
* Enable flowtype for buildConsoleReplay.js
* Enable flowtype for generatorFunction.js

node_package/.babelrc

@@ -1,4 +1,7 @@
 {
   "presets": ["es2015", "stage-0", "react"],
-  "plugins": ["transform-runtime"]
+  "plugins": [
+    "transform-flow-strip-types",
+    "transform-runtime"
+  ]
 }

node_package/.flowconfig

@@ -0,0 +1,3 @@
+[ignore]
+.*/lib/.*
+.*/node_modules/.*

node_package/src/Authenticity.js

@@ -1,11 +1,13 @@
+// @flow
+
 export default {
 
   authenticityToken() {
-    const token = document.querySelector('meta[name="csrf-token"]');
+    const token: {content?: string} = document.querySelector('meta[name="csrf-token"]');
     return token ? token.content : null;
   },
 
-  authenticityHeaders(otherHeaders = {}) {
+  authenticityHeaders(otherHeaders: {[id:string]: string} = {}) {
     return Object.assign(otherHeaders, {
       'X-CSRF-Token': this.authenticityToken(),
       'X-Requested-With': 'XMLHttpRequest',

node_package/src/buildConsoleReplay.js

@@ -1,14 +1,15 @@
+// @flow
+
 import RenderUtils from './RenderUtils';
 import scriptSanitizedVal from './scriptSanitizedVal';
 
 export function consoleReplay() {
   // console.history is a global polyfill used in server rendering.
-  const history = console.history;
-  if (!history || history.length === 0) {
+  if (!(console.history instanceof Array)) {
     return '';
   }
 
-  const lines = history.map(msg => {
+  const lines = console.history.map(msg => {
     const stringifiedList = msg.arguments.map(arg => {
       let val;
       try {

node_package/src/context.js

@@ -1,3 +1,5 @@
+// @flow
+
 /**
  * Get the context, be it window or global
  * @returns {boolean|Window|*|context}

node_package/src/generatorFunction.js

@@ -1,3 +1,5 @@
+// @flow
+
 // See discussion:
 // https://discuss.reactjs.org/t/how-to-determine-if-js-object-is-react-component/2825/2
 
@@ -7,12 +9,11 @@
  * @param component
  * @returns {boolean}
  */
-export default function generatorFunction(component) {
+export default function generatorFunction(component: any) {
   if (!component.prototype) {
     return false;
   }
 
   // es5 or es6 React Component
-  const es5OrEs6ReactComponent = component.prototype.isReactComponent;
-  return !es5OrEs6ReactComponent;
+  return !component.prototype.isReactComponent;
 }

package.json

@@ -11,6 +11,7 @@
     "babel-core": "^6.7.4",
     "babel-loader": "^6.2.4",
     "babel-plugin-react-transform": "^2.0.2",
+    "babel-plugin-transform-flow-strip-types": "^6.8.0",
     "babel-plugin-transform-runtime": "^6.6.0",
     "babel-preset-es2015": "^6.6.0",
     "babel-preset-react": "^6.5.0",
@@ -25,6 +26,7 @@
     "eslint-plugin-import": "^1.13.0",
     "eslint-plugin-jsx-a11y": "^2.1.0",
     "eslint-plugin-react": "^6.1.2",
+    "flow-bin": "^0.30.0",
     "jscs": "^2.11.0",
     "jsdom": "^8.2.0",
     "react": "^15.0.0",
@@ -53,7 +55,8 @@
     "build-watch": "babel --watch --out-dir node_package/lib node_package/src",
     "eslint": "eslint .",
     "jscs": "jscs -e -v .",
-    "lint": "npm run eslint && npm run jscs",
+    "flow": "flow check node_package",
+    "lint": "npm run eslint && npm run jscs && npm run flow",
     "lint:fix": "node_package/scripts/lint-fix",
     "check": "npm run lint && npm run test",
     "prerelease": "npm run check && npm run clean && npm run build",

rakelib/lint.rake

@@ -28,8 +28,13 @@ namespace :lint do
     sh_in_dir(gem_root, "npm run jscs")
   end
 
-  desc "Run all eslint, jscs, rubocop linters. Skip ruby-lint and scss"
-  task lint: [:eslint, :jscs, :rubocop] do
+  desc "Run flow from shell"
+  task :flow do
+    sh_in_dir(gem_root, "npm run flow")
+  end
+
+  desc "Run all eslint, jscs, flow, rubocop linters. Skip ruby-lint and scss"
+  task lint: [:eslint, :jscs, :flow, :rubocop] do
     puts "Completed all linting"
   end
 end