chore: add eslint and fix errors

Author: hudovisk

.eslintrc.json

@@ -0,0 +1,5 @@
+{
+  "settings": { "react": { "version": "detect" } },
+  "parser": "babel-eslint",
+  "extends": ["plugin:react/recommended", "plugin:prettier/recommended"]
+}

package.json

@@ -5,16 +5,19 @@
   "repository": "hudovisk/react-optimize",
   "license": "MIT",
   "scripts": {
+    "lint:fix": "yarn lint --fix",
+    "lint": "eslint src/ test/",
     "test:node": "mocha --require @babel/register test/test.node.js",
     "test:browser": "cross-env NODE_ENV=test karma start",
-    "test": "yarn run test:node && yarn run test:browser",
+    "test": "yarn run test:node && yarn run test:browser && yarn run lint",
     "build": "webpack",
     "watch": "webpack --watch",
     "prepublishOnly": "yarn run build"
   },
   "husky": {
     "hooks": {
-      "commit-msg": "commitlint -E HUSKY_GIT_PARAMS"
+      "commit-msg": "commitlint -E HUSKY_GIT_PARAMS",
+      "pre-commit": "yarn run lint"
     }
   },
   "devDependencies": {
@@ -26,11 +29,16 @@
     "@babel/register": "^7.4.0",
     "@commitlint/cli": "^8.2.0",
     "@commitlint/config-conventional": "^8.2.0",
+    "babel-eslint": "^10.0.3",
     "babel-loader": "^8.0.4",
     "chai": "^4.2.0",
     "cross-env": "^6.0.3",
     "enzyme": "^3.9.0",
     "enzyme-adapter-react-16": "^1.12.1",
+    "eslint": "^6.7.2",
+    "eslint-config-prettier": "^6.7.0",
+    "eslint-plugin-prettier": "^3.1.1",
+    "eslint-plugin-react": "^7.17.0",
     "husky": "^3.1.0",
     "karma": "^4.1.0",
     "karma-chrome-launcher": "^3.1.0",
@@ -40,6 +48,7 @@
     "karma-sourcemap-loader": "^0.3.7",
     "karma-webpack": "^4.0.2",
     "mocha": "^6.1.3",
+    "prettier": "^1.19.1",
     "react": "^16.8.6",
     "react-dom": "^16.8.6",
     "semantic-release": "^15.13.3",

src/Experiment.js

@@ -47,18 +47,20 @@ class Experiment extends React.Component {
       this.delayedInitialization();
     }
 
-    window.gtag && window.gtag("event", "optimize.callback", {
-      name: this.props.id,
-      callback: this.updateVariant
-    });
+    window.gtag &&
+      window.gtag("event", "optimize.callback", {
+        name: this.props.id,
+        callback: this.updateVariant
+      });
   }
 
   componentWillUnmount() {
-    window.gtag && window.gtag("event", "optimize.callback", {
-      name: this.props.id,
-      callback: this.updateVariant,
-      remove: true
-    });
+    window.gtag &&
+      window.gtag("event", "optimize.callback", {
+        name: this.props.id,
+        callback: this.updateVariant,
+        remove: true
+      });
   }
 
   render() {
@@ -70,4 +72,4 @@ class Experiment extends React.Component {
   }
 }
 
-export default Experiment;
+export default Experiment;