Adding ESLint to the project and solving the ESLint Errors

.eslintignore

@@ -0,0 +1,16 @@
+package.json
+package-lock.json
+node_modules/
+.DS_Store
+*.html
+.gitignore
+.prettierignore
+.prettierrc
+AUTHORS
+CHECKS
+docker-compose.yml
+Dockerfile
+LICENSE
+nightwatch.conf.js
+README.md
+client-data/

.eslintrc.js

@@ -0,0 +1,35 @@
+module.exports = {
+  env: {
+    commonjs: true,
+    es2021: true,
+    node: true,
+  },
+  extends: "eslint:recommended",
+  overrides: [
+    {
+      env: {
+        node: true,
+      },
+      files: [".eslintrc.{js,cjs}"],
+      parserOptions: {
+        sourceType: "script",
+      },
+    },
+  ],
+  parserOptions: {
+    ecmaVersion: "latest",
+  },
+  globals: {
+    Tools: true,
+  },
+  rules: {
+    "no-prototype-builtins": "off",
+    "no-unused-vars": [
+      "error",
+      { argsIgnorePattern: "^_", varsIgnorePattern: "^_" },
+    ],
+    semi: ["error", "always"],
+    "no-cond-assign": ["error", "always"],
+    curly: "error",
+  },
+};

.github/workflows/CI.yml

@@ -34,10 +34,23 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Install dependencies
         run: npm install
 
       - name: Run Prettier check
         run: npx prettier --check .
+
+  lint:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v3
+
+      - name: Install dependencies
+        run: npm install
+
+      - name: Run ESLint
+        run: npx eslint .

client-data/js/intersect.js

@@ -59,8 +59,8 @@ if (
     };
 
     SVGGraphicsElement.prototype.transformedBBox = function (scale = 1) {
-      bbox = this.getBBox();
-      tmatrix = get_transform_matrix(this);
+      var bbox = this.getBBox();
+      var tmatrix = get_transform_matrix(this);
       tmatrix.e /= scale;
       tmatrix.f /= scale;
       return {
@@ -71,13 +71,13 @@ if (
     };
 
     SVGSVGElement.prototype.transformedBBox = function (scale = 1) {
-      bbox = {
+      var bbox = {
         x: this.x.baseVal.value,
         y: this.y.baseVal.value,
         width: this.width.baseVal.value,
         height: this.height.baseVal.value,
       };
-      tmatrix = get_transform_matrix(this);
+      var tmatrix = get_transform_matrix(this);
       tmatrix.e /= scale;
       tmatrix.f /= scale;
       return {