Add description for js rules (#1946)

We introduced a new set of lint rules targeting JS implementation files,
instead of just .cds files.
This PR introduces automatic documentation extraction for these new
rules, to be found in list form under `/tools/cds-lint/rules/`

![Screenshot 2025-07-02 at 12 39
12](https://github.com/user-attachments/assets/987bbfdc-063b-4130-ba66-239900cb008e)

We do not yet introduce extended documentation per rule for these new
rules, as I am not clear yet whether they are automatically generated or
maintained manually.

Co-authored-by: Christian Georgi <chgeo@users.noreply.github.com>
Co-authored-by: René Jeglinsky <rene.jeglinsky@sap.com>

Author: 3 people

tools/cds-lint/rules.data.ts

@@ -3,34 +3,56 @@ import * as path from 'path'
 
 export default {
   async load() {
-    const data: any = { "Model Validation": [], "Environment": [] };
+    const data: any = { "Model Validation": [], "Environment": [], "Javascript": [] };
     let plugin: any;
     try {
       // @ts-ignore
       plugin = (await import('@sap/eslint-plugin-cds')).default;
-    } catch (e) {
+    } catch {
       return data
     }
-    const allRules = Object.keys(plugin.configs.all.rules).sort();
-
-    allRules.forEach((rule: string) => {
-      rule = rule.replace('@sap/cds/', '');
-      const description = md2Html(plugin.rules[rule]?.meta.docs.description);
-      const ruleDocs = path.join(__dirname, `rules/${rule}.md`)
-      const hasRuleDocs = fs.existsSync(ruleDocs)
-      const url = hasRuleDocs ? `./${rule}` : null
-      const isRecommended = plugin.rules[rule]?.meta.docs.recommended ? '✅' : '';
-      const hasFix = plugin.rules[rule]?.meta.fixable ? '🔧' : '';
-      const hasSuggestions = plugin.rules[rule]?.meta.hasSuggestions ? '💡' : '';
-      const model = plugin.rules[rule]?.meta?.model === 'parsed' ? '👀' : '';
-      const category = plugin.rules[rule]?.meta?.model === 'none' ? "Environment" : "Model Validation";
-      data[category].push({ rule, description, url, isRecommended, hasFix, hasSuggestions, model })
-    })
+    const allCdsRules = Object.keys(plugin.configs.all.rules)
+    .map((ruleName: string) => ruleName.replace('@sap/cds/', ''))
+    .sort();
+
+    for (const cdsRuleName of allCdsRules) {
+      const rule = plugin.rules[cdsRuleName]
+      const model = rule.meta?.model
+      const category = model === 'none' ? 'Environment' : 'Model Validation';
+      
+      data[category].push({...ruleInfo(cdsRuleName, rule),
+        model: model === 'parsed' ? '👀' : ''
+      })
+    }
+
+    const allJsRuleName = Object.keys(plugin.configs.js.all.rules)
+      .map((ruleName: string) => ruleName.replace('@sap/cds/', ''))
+      .sort();
+
+    for (const jsRuleName of allJsRuleName) {
+      data.Javascript.push(ruleInfo(jsRuleName, plugin.rules[jsRuleName]))
+    }
+
     return data;
   }
 
 }
 
+function ruleInfo (name, rule) {
+  const meta = rule.meta ?? {}
+  const ruleDocs = path.join(__dirname, `rules/${name}.md`)
+  const hasRuleDocs = fs.existsSync(ruleDocs)
+  return {
+    rule: name,
+    description: md2Html(meta.docs.description),
+    url: hasRuleDocs ? `./${name}` : null,
+    isRecommended: meta.docs?.recommended ? '✅' : '',
+    hasFix: meta.fixable ? '🔧' : '',
+    hasSuggestions: meta.hasSuggestions ? '💡' : '',
+    model: meta.model === 'parsed' ? '👀' : ''
+  }
+}
+
 function md2Html(string:string='') {
   return string
     // @ts-ignore

tools/cds-lint/rules/index.md

@@ -42,3 +42,10 @@ These are only run via the command line and are not available in the editor as t
 pinpointed to any particular file.
 
 <RulesRefTable category="Environment"/>
+
+
+## JavaScript
+
+JavaScript rules are designed to catch bad practices and common mistakes when implementing custom JavaScript handlers in CDS projects. These rules help ensure code quality, maintainability, and adherence to best practices when extending CDS with JavaScript logic.
+
+<RulesRefTable category="Javascript"/>