Adds EsLint

Adds eslint, eslint rules, and updates the workflow file. Adds a yarn
command to run linting.

Signed-off-by: Hassan Abouelela <[email protected]>

4 files changed, 59 insertions, 3 deletions

diff --git a/.eslintrc.json b/.eslintrc.json
new file mode 100644
index 0000000..4e55622
--- /dev/null
+++ b/.eslintrc.json
@@ -0,0 +1,41 @@
+{
+    "env": {
+        "browser": true,
+        "es2021": true
+    },
+    "extends": [
+        "eslint:recommended",
+        "plugin:react/recommended",
+        "plugin:@typescript-eslint/recommended"
+    ],
+    "parser": "@typescript-eslint/parser",
+    "parserOptions": {
+        "ecmaFeatures": {
+            "jsx": true
+        },
+        "ecmaVersion": 12,
+        "sourceType": "module"
+    },
+    "plugins": [
+        "react",
+        "@typescript-eslint"
+    ],
+    "rules": {
+        "indent": [
+            "error",
+            4
+        ],
+        "linebreak-style": [
+            "error",
+            "unix"
+        ],
+        "quotes": [
+            "error",
+            "double"
+        ],
+        "semi": [
+            "error",
+            "always"
+        ]
+    }
+}
diff --git a/.github/workflows/test_and_lint.yml b/.github/workflows/test_and_lint.yml
index e7a0d05..636e181 100644
--- a/.github/workflows/test_and_lint.yml
+++ b/.github/workflows/test_and_lint.yml
@@ -32,5 +32,16 @@ jobs:
 
       - name: Run tests
         run: yarn test
-      
-      
+
+  lint:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+      - uses: EgorDm/gha-yarn-node-cache@v1
+
+      - name: Install dependencies
+        run: yarn install --dev
+
+      - name: Lint
+        run: yarn run eslint --ext .ts,.tsx --quiet src/
diff --git a/.gitignore b/.gitignore
index 8692cf6..3ac9558 100644
--- a/.gitignore
+++ b/.gitignore
@@ -8,6 +8,9 @@
 # testing
 /coverage
 
+# linting
+.eslintcache
+
 # production
 /build
 
diff --git a/package.json b/package.json
index 059077c..641fe19 100644
--- a/package.json
+++ b/package.json
@@ -38,7 +38,8 @@
   "scripts": {
     "start": "cross-env NODE_ENV=development webpack serve",
     "build": "cross-env REACT_APP_SHA=$COMMIT_REF REACT_APP_BRANCH=$BRANCH webpack",
-    "test": "cross-env jest"
+    "test": "cross-env jest",
+    "lint": "cross-env eslint --cache src/"
   },
   "eslintConfig": {
     "extends": "react-app"