Adding eslint (#32)

* adding eslint dev-dependency

* prettify existing code

* aligning prettier with eslint config

.eslintrc.json

@@ -0,0 +1,39 @@
+{
+    "env": {
+        "browser": true,
+        "commonjs": true,
+        "es2021": true,
+        "node": true,
+        "jest/globals": true
+    },
+    "plugins": ["jest"],
+    "extends": [
+        "prettier"
+    ],
+    "overrides": [
+    ],
+    "parserOptions": {
+        "ecmaVersion": "latest"
+    },
+    "rules": {
+        "indent": [
+            "error",
+            4,
+            {"SwitchCase": 1}
+        ],
+        "linebreak-style": [
+            "error",
+            "unix"
+        ],
+        "quotes": [
+            "error",
+            "single",
+            {"avoidEscape": true}
+        ],
+        "semi": [
+            "error",
+            "never"
+        ],
+        "jest/no-identical-title": "error"
+    }
+}

.npmignore

@@ -9,4 +9,5 @@ scripts/
 .watchmanconfig
 .prettierrc.json
 .prettierignore
+.eslintrc.json
 rollup.config.js

.prettierrc.json

@@ -1,5 +1,6 @@
 {
     "tabWidth": 4,
+    "useTabs": false,
     "semi": false,
     "singleQuote": true,
     "trailingComma": "none"