Adding of eslint.

1. Adding of eslint warning disables to app.js
2. Installing of eslint dependencies to the project.
3. Adding of eslint.config.mjs.

Author: Mohammed-AbdulRahman-Apryse

app/app.js

@@ -1,21 +1,23 @@
+/* eslint-disable-next-line no-undef */
 WebViewer({
   path: 'lib', // path to the PDFTron 'lib' folder on your server
   // licenseKey: 'Insert commercial license key here after purchase',
   initialDoc: 'https://pdftron.s3.amazonaws.com/downloads/pl/demo-annotated.pdf',
   // initialDoc: '/path/to/my/file.pdf',  // You can also use documents on your server
 }, document.getElementById('viewer'))
-.then(function(instance) {
-  const { documentViewer, annotationManager } = instance.Core;
-  // call methods from instance, documentViewer and annotationManager as needed
+  .then(function(instance) {
+    const { documentViewer, annotationManager } = instance.Core;
+    // call methods from instance, documentViewer and annotationManager as needed
 
-  // you can also access major namespaces from the instance as follows:
-  // const Tools = instance.Core.Tools;
-  // const Annotations = instance.Core.Annotations;
+    // you can also access major namespaces from the instance as follows:
+    // const Tools = instance.Core.Tools;
+    // const Annotations = instance.Core.Annotations;
 
-  // change to dark theme
-  instance.UI.setTheme('dark');
+    // change to dark theme
+    instance.UI.setTheme('dark');
 
-  documentViewer.addEventListener('documentLoaded', function() {
+    documentViewer.addEventListener('documentLoaded', function() {
     // call methods relating to the loaded document
+    });
   });
-});
+/*eslint no-unused-vars: "warn"*/

eslint.config.mjs

@@ -0,0 +1,77 @@
+import js from "@eslint/js";
+import globals from "globals";
+
+export default [
+  js.configs.recommended,
+  { ignores: ["**/node_modules/", "**/.git/", "**/app/lib/*"] },
+  { files: ["**/*.{js,mjs}"] },
+  {
+    languageOptions: {
+      ecmaVersion: "latest",
+      sourceType: "module",
+      globals: {
+        ...globals.browser,
+        ...globals.node
+      }
+    },
+    "rules": {
+      "quotes": [
+        0,
+        "single",
+        {
+          "allowTemplateLiterals": true
+        }
+      ],
+      "curly": 2,
+      "strict": [2, "never"],
+      "semi": [2, "always"],
+      "no-redeclare": [
+        2,
+        {
+          "builtinGlobals": true
+        }
+      ],
+      "brace-style": 2,
+      "no-alert": 0,
+      "no-console": [
+        0,
+        {
+          "allow": ["warn", "error"]
+        }
+      ],
+      "object-shorthand": [2, "always"],
+      "arrow-parens": [2, "as-needed"],
+      "no-useless-escape": 0,
+      "eqeqeq": 2,
+      "jsx-quotes": 2,
+      "indent": [
+        2,
+        2,
+        {
+          "MemberExpression": 1,
+          "ArrayExpression": 1,
+          "ImportDeclaration": 1,
+          "SwitchCase": 1,
+          "FunctionExpression": {
+            "body": 1
+          }
+        }
+      ],
+      "keyword-spacing": 2,
+      "space-before-blocks": 2,
+      "arrow-spacing": 2,
+      "object-curly-spacing": [2, "always"],
+      "@pdftron/webviewer/no-string-events": 0,
+
+      // these are inherited from git WebViewer's eslint configuration
+      "no-use-before-define": 0,
+      "implicit-arrow-linebreak": 0,
+      "operator-linebreak": 0,
+      "function-paren-newline": 0,
+      "object-curly-newline": 0,
+      "no-nested-ternary": 0,
+      "no-unexpected-multiline": 0,
+      "no-unused-expressions": 0
+    }
+  }
+];

package.json

@@ -4,14 +4,17 @@
   "scripts": {
     "start": "concurrently \"npm run server\" \"start http://localhost:3000\"",
     "server": "supervisor -k -e html,js -i .git/,node_modules/ -- server.js",
-    "postinstall": "node tools/copy-webviewer-files.js"
+    "postinstall": "node tools/copy-webviewer-files.js",
+    "lint": "eslint --fix ."
   },
   "repository": {
     "type": "git",
     "url": ""
   },
   "author": "PDFTron Systems Inc.",
   "devDependencies": {
+    "@eslint/js": "^9.9.1",
+    "eslint": "^9.9.1",
     "body-parser": "^1.20.2",
     "express": "^4.19.2",
     "fs-extra": "^11.2.0",

server.js

@@ -1,27 +1,27 @@
 // modified original source from https://www.npmjs.com/package/reload#using-reload-in-express
 
-var express = require('express')
-var http = require('http')
-var path = require('path')
-var bodyParser = require('body-parser')
-var logger = require('morgan')
+var express = require('express');
+var http = require('http');
+var path = require('path');
+var bodyParser = require('body-parser');
+var logger = require('morgan');
 
-var app = express()
+var app = express();
 
-var appDir = path.join(__dirname, 'app')
+var appDir = path.join(__dirname, 'app');
 
-app.set('port', process.env.PORT || 3000)
-app.use(logger('dev'))
-app.use(bodyParser.json()) // Parses json, multi-part (file), url-encoded
+app.set('port', process.env.PORT || 3000);
+app.use(logger('dev'));
+app.use(bodyParser.json()); // Parses json, multi-part (file), url-encoded
 
 app.get('/', function (req, res) {
-  res.sendFile(path.join(appDir, 'index.html'))
-})
+  res.sendFile(path.join(appDir, 'index.html'));
+});
 
 app.use(express.static(appDir));
 
-var server = http.createServer(app)
+var server = http.createServer(app);
 
 server.listen(app.get('port'), function () {
-  console.log('Web server listening on port ' + app.get('port'))
-})
+  console.log('Web server listening on port ' + app.get('port'));
+});