feat(js): Make flow work

tl;dr use `flow-check` script to typecheck code.

Add a babel plugin to strip out type declarations from resulting code,
thus making it possible to actually write them and have things working
afterwards.

Also brings in `flow-result-checker`, an ugly workaround for
facebook/flow#869 - the tl;dr is Flow reports
type errors in all the `//@flow`'ed files, including ones in
`node_modules` - which isn't entirely helpful.

This affects us due to expo/ex-navigation#87,
the tl;dr for which is ex-navigation has type errors and no one seems
to be working on it ATM.

So, code can currently be typechecked as mentioned at the top of the
commit message; also, one of the components has been annotated to demonstrate.

telemetry_ga_android/.babelrc

@@ -2,5 +2,8 @@
   "presets": [
     "react-native",
     "react-native-stage-0/decorator-support",
-  ]
+  ],
+  "plugins": [
+    "transform-flow-strip-types",
+  ],
 }

telemetry_ga_android/.flowconfig

@@ -19,7 +19,6 @@
 [libs]
 node_modules/react-native/Libraries/react-native/react-native-interface.js
 node_modules/react-native/flow
-flow/
 
 [options]
 module.system=haste

telemetry_ga_android/SwitchingComponent.js

@@ -1,4 +1,7 @@
-export default (props) => {
-  const i = Math.trunc(props.flex_count / 25) % props.sources.length;
-  return props.sources[i];
+// @flow
+export default ({ flex_count, sources }:
+                { flex_count: number,
+                  sources: Array<ReactClass<*>> }) => {
+  const i = Math.trunc(flex_count / 25) % sources.length;
+  return sources[i];
 };

telemetry_ga_android/package.json

@@ -2,10 +2,12 @@
   "name": "@motorica-org/telemetry_ga_android",
   "version": "0.1.0",
   "scripts": {
-    "start": "node node_modules/react-native/local-cli/cli.js start"
+    "start": "node node_modules/react-native/local-cli/cli.js start",
+    "flow-check": "flow check | flow-result-checker"
   },
   "dependencies": {
     "@exponent/ex-navigation": "^2.7.1",
+    "babel-plugin-transform-flow-strip-types": "^6.22.0",
     "babel-preset-react-native-stage-0": "^1.0.1",
     "react": "^15.4.2",
     "react-native": "^0.40.0",
@@ -18,6 +20,8 @@
     "eslint-config-airbnb": "^14.0.0",
     "eslint-plugin-import": "^2.2.0",
     "eslint-plugin-jsx-a11y": "^3.0.2",
-    "eslint-plugin-react": "^6.9.0"
+    "eslint-plugin-react": "^6.9.0",
+    "flow-bin": "0.36.0",
+    "flow-result-checker": "^0.1.1"
   }
 }

telemetry_ga_android/yarn.lock

@@ -602,7 +602,7 @@ babel-plugin-transform-export-extensions@^6.5.0:
     babel-plugin-syntax-export-extensions "^6.8.0"
     babel-runtime "^6.22.0"
 
-babel-plugin-transform-flow-strip-types@^6.18.0, babel-plugin-transform-flow-strip-types@^6.5.0, babel-plugin-transform-flow-strip-types@^6.7.0, babel-plugin-transform-flow-strip-types@^6.8.0:
+babel-plugin-transform-flow-strip-types@^6.18.0, babel-plugin-transform-flow-strip-types@^6.22.0, babel-plugin-transform-flow-strip-types@^6.5.0, babel-plugin-transform-flow-strip-types@^6.7.0, babel-plugin-transform-flow-strip-types@^6.8.0:
   version "6.22.0"
   resolved "https://registry.yarnpkg.com/babel-plugin-transform-flow-strip-types/-/babel-plugin-transform-flow-strip-types-6.22.0.tgz#84cb672935d43714fdc32bce84568d87441cf7cf"
   dependencies:
@@ -1011,6 +1011,16 @@ cli-cursor@^1.0.1:
   dependencies:
     restore-cursor "^1.0.1"
 
+cli-cursor@^2.1.0:
+  version "2.1.0"
+  resolved "https://registry.yarnpkg.com/cli-cursor/-/cli-cursor-2.1.0.tgz#b35dac376479facc3e94747d41d0d0f5238ffcb5"
+  dependencies:
+    restore-cursor "^2.0.0"
+
+cli-spinners@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/cli-spinners/-/cli-spinners-1.0.0.tgz#ef987ed3d48391ac3dab9180b406a742180d6e6a"
+
 cli-width@^2.0.0:
   version "2.1.0"
   resolved "https://registry.yarnpkg.com/cli-width/-/cli-width-2.1.0.tgz#b234ca209b29ef66fc518d9b98d5847b00edf00a"
@@ -1707,6 +1717,19 @@ flat-cache@^1.2.1:
     graceful-fs "^4.1.2"
     write "^0.2.1"
 
+[email protected]:
+  version "0.36.0"
+  resolved "https://registry.yarnpkg.com/flow-bin/-/flow-bin-0.36.0.tgz#557907bd9c2ab0670cfad9e7e906a74b0631e39a"
+
+flow-result-checker@^0.1.1:
+  version "0.1.1"
+  resolved "https://registry.yarnpkg.com/flow-result-checker/-/flow-result-checker-0.1.1.tgz#b42431448c312bb5059c17435e7da8df95f6a26c"
+  dependencies:
+    chalk "^1.1.3"
+    commander "^2.9.0"
+    mkdirp "^0.5.1"
+    ora "^1.1.0"
+
 foreach@^2.0.5:
   version "2.0.5"
   resolved "https://registry.yarnpkg.com/foreach/-/foreach-2.0.5.tgz#0bee005018aeb260d0a3af3ae658dd0136ec1b99"
@@ -2379,6 +2402,12 @@ lodash@^4.0.0, lodash@^4.14.0, lodash@^4.16.6, lodash@^4.2.0, lodash@^4.2.1, lod
   version "4.17.4"
   resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.4.tgz#78203a4d1c328ae1d86dca6460e369b57f4055ae"
 
+log-symbols@^1.0.2:
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/log-symbols/-/log-symbols-1.0.2.tgz#376ff7b58ea3086a0f09facc74617eca501e1a18"
+  dependencies:
+    chalk "^1.0.0"
+
 longest@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/longest/-/longest-1.0.1.tgz#30a0b2da38f73770e8294a0d22e6625ed77d0097"
@@ -2447,6 +2476,10 @@ [email protected], mime@^1.3.4:
   version "1.3.4"
   resolved "https://registry.yarnpkg.com/mime/-/mime-1.3.4.tgz#115f9e3b6b3daf2959983cb38f149a2d40eb5d53"
 
+mimic-fn@^1.0.0:
+  version "1.1.0"
+  resolved "https://registry.yarnpkg.com/mimic-fn/-/mimic-fn-1.1.0.tgz#e667783d92e89dbd342818b5230b9d62a672ad18"
+
 min-document@^2.19.0:
   version "2.19.0"
   resolved "https://registry.yarnpkg.com/min-document/-/min-document-2.19.0.tgz#7bd282e3f5842ed295bb748cdd9f1ffa2c824685"
@@ -2609,6 +2642,12 @@ onetime@^1.0.0:
   version "1.1.0"
   resolved "https://registry.yarnpkg.com/onetime/-/onetime-1.1.0.tgz#a1f7838f8314c516f05ecefcbc4ccfe04b4ed789"
 
+onetime@^2.0.0:
+  version "2.0.0"
+  resolved "https://registry.yarnpkg.com/onetime/-/onetime-2.0.0.tgz#52aa8110e52fc5126ffc667bd8ec21c2ed209ce6"
+  dependencies:
+    mimic-fn "^1.0.0"
+
 opn@^3.0.2:
   version "3.0.3"
   resolved "https://registry.yarnpkg.com/opn/-/opn-3.0.3.tgz#b6d99e7399f78d65c3baaffef1fb288e9b85243a"
@@ -2637,6 +2676,15 @@ options@>=0.0.5:
   version "0.0.6"
   resolved "https://registry.yarnpkg.com/options/-/options-0.0.6.tgz#ec22d312806bb53e731773e7cdaefcf1c643128f"
 
+ora@^1.1.0:
+  version "1.1.0"
+  resolved "https://registry.yarnpkg.com/ora/-/ora-1.1.0.tgz#69aaa4a209630e43b142c5f7ff41820da87e2faf"
+  dependencies:
+    chalk "^1.1.1"
+    cli-cursor "^2.1.0"
+    cli-spinners "^1.0.0"
+    log-symbols "^1.0.2"
+
 os-homedir@^1.0.0:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/os-homedir/-/os-homedir-1.0.2.tgz#ffbc4988336e0e833de0c168c7ef152121aa7fb3"
@@ -3143,6 +3191,13 @@ restore-cursor@^1.0.1:
     exit-hook "^1.0.0"
     onetime "^1.0.0"
 
+restore-cursor@^2.0.0:
+  version "2.0.0"
+  resolved "https://registry.yarnpkg.com/restore-cursor/-/restore-cursor-2.0.0.tgz#9f7ee287f82fd326d4fd162923d62129eee0dfaf"
+  dependencies:
+    onetime "^2.0.0"
+    signal-exit "^3.0.2"
+
 right-align@^0.1.1:
   version "0.1.3"
   resolved "https://registry.yarnpkg.com/right-align/-/right-align-0.1.3.tgz#61339b722fe6a3515689210d24e14c96148613ef"
@@ -3263,6 +3318,10 @@ shelljs@^0.7.5:
     interpret "^1.0.0"
     rechoir "^0.6.2"
 
+signal-exit@^3.0.2:
+  version "3.0.2"
+  resolved "https://registry.yarnpkg.com/signal-exit/-/signal-exit-3.0.2.tgz#b5fdc08f1287ea1178628e415e25132b73646c6d"
+
 [email protected]:
   version "0.1.4"
   resolved "https://registry.yarnpkg.com/simple-plist/-/simple-plist-0.1.4.tgz#10eb51b47e33c556eb8ec46d5ee64d64e717db5d"