Add flow annotation

.eslintrc.json

@@ -1,6 +1,8 @@
 {
     "extends": [
-      "eslint:recommended"
+      "eslint:recommended",
+      "plugin:flowtype/recommended",
+      "plugin:react/recommended"
     ],
     "rules": {
         "array-bracket-spacing": ["error", "always"],
@@ -21,14 +23,51 @@
         "object-curly-spacing": ["error", "always"],
         "quotes": ["error", "single"],
         "semi": ["error", "always" ],
-        "space-infix-ops": "error"
+        "space-infix-ops": "error",
+
+        "react/jsx-key": "error",
+        "react/jsx-no-bind": ["error", {
+          "ignoreRefs": true
+        }],
+        "react/no-unused-prop-types": "error",
+        "react/prefer-es6-class": "error",
+        "react/prop-types": [
+          "error", {
+            "ignore": [
+              "children",
+              "dispatch"
+            ]
+          }
+        ],
+
+        "react-native/no-inline-styles": "error",
+        "react-native/no-unused-styles": "error",
+        "react-native/split-platform-components": "warn"
     },
     "env": {
         "es6": true,
         "node": true
     },
+    "parser": "babel-eslint",
     "parserOptions": {
-        "ecmaVersion": 6,
+        "ecmaVersion": 8,
+        "ecmaFeatures": {
+            "jsx": true
+        },
         "sourceType": "module"
+    },
+    "settings": {
+      "flowtype": {
+        "onlyFilesWithFlowAnnotation": true
+      },
+      "react": {
+        "pragma": "React",
+        "version": "16.0.0"
       }
+    },
+    "plugins": [
+      "flowtype",
+      "react",
+      "react-native"
+    ]
 }

.flowconfig

@@ -0,0 +1,31 @@
+[ignore]
+
+[include]
+
+[libs]
+node_modules/react-native/Libraries/react-native/react-native-interface.js
+node_modules/react-native/flow
+flow/
+
+[options]
+emoji=true
+
+module.system=haste
+
+munge_underscores=true
+
+module.name_mapper='^[./a-zA-Z0-9$_-]+\.\(bmp\|gif\|jpg\|jpeg\|png\|psd\|svg\|webp\|m4v\|mov\|mp4\|mpeg\|mpg\|webm\|aac\|aiff\|caf\|m4a\|mp3\|wav\|html\|pdf\)$' -> 'RelativeImageStub'
+
+suppress_type=$FlowIssue
+suppress_type=$FlowFixMe
+suppress_type=$FixMe
+
+suppress_comment=\\(.\\|\n\\)*\\$FlowFixMe\\($\\|[^(]\\|(\\(>=0\\.\\(4[0-9]\\|[1-3][0-9]\\|[0-9]\\).[0-9]\\)? *\\(site=[a-z,_]*react_native[a-z,_]*\\)?)\\)
+suppress_comment=\\(.\\|\n\\)*\\$FlowIssue\\((\\(>=0\\.\\(4[0-9]\\|[1-3][0-9]\\|[0-9]\\).[0-9]\\)? *\\(site=[a-z,_]*react_native[a-z,_]*\\)?)\\)?:? #[0-9]+
+suppress_comment=\\(.\\|\n\\)*\\$FlowFixedInNextDeploy
+suppress_comment=\\(.\\|\n\\)*\\$FlowExpectedError
+
+unsafe.enable_getters_and_setters=true
+
+[version]
+^0.49.1

index.js

@@ -1,3 +1,5 @@
+// @flow
+
 import { NativeModules } from 'react-native';
 const { AppMetrica } = NativeModules;
 
@@ -7,7 +9,7 @@ export default {
      * Starts the statistics collection process.
      * @param {string} apiKey
      */
-    activateWithApiKey(apiKey) {
+    activateWithApiKey(apiKey: string) {
         AppMetrica.activateWithApiKey(apiKey);
     },
 
@@ -16,7 +18,7 @@ export default {
      * @param {string} message
      * @param {object} [params=null]
      */
-    reportEvent(message, params = null) {
+    reportEvent(message: string, params: ?Object = null) {
         AppMetrica.reportEvent(message, params);
     },
 
@@ -25,7 +27,7 @@ export default {
      * @param {string} error
      * @param {object} reason
      */
-    reportError(error, reason) {
+    reportError(error: string, reason: Object) {
         AppMetrica.reportError(error, reason);
     },
 };

package.json

@@ -28,6 +28,11 @@
     "react-native": ">=0.45"
   },
   "devDependencies": {
-    "eslint": "^4.7.0"
+    "babel-eslint": "^8.0.1",
+    "eslint": "^4.7.0",
+    "eslint-plugin-flowtype": "^2.37.0",
+    "eslint-plugin-react": "^7.4.0",
+    "eslint-plugin-react-native": "^3.1.0",
+    "flow-bin": "0.49.1"
   }
 }