refactor: reduce nextToken() cognitive complexity from 17 to 15

src/codegen.ts

@@ -1049,7 +1049,7 @@ export class CodeGenerator {
     result += this.indent(`const ${name} = {};\n`);
 
     // Generate namespace body
-    if (node.body && node.body.statements) {
+    if (node.body?.statements) {
       for (const stmt of node.body.statements) {
         const isExported = (stmt as Statement & { exported?: boolean }).exported;
 
@@ -1127,7 +1127,7 @@ export class CodeGenerator {
         return (stmt as FunctionDeclaration).name.name;
       case 'VariableDeclaration': {
         const varDecl = stmt as VariableDeclaration;
-        if (varDecl.identifier && varDecl.identifier.type === 'Identifier') {
+        if (varDecl.identifier?.type === 'Identifier') {
           return varDecl.identifier.name;
         }
         break;
@@ -1150,7 +1150,7 @@ export class CodeGenerator {
     let classBody = '';
 
     // Generate class members
-    if (node.body && node.body.body) {
+    if (node.body?.body) {
       const members = node.body.body
         .map(member => {
           switch (member.type) {
@@ -1192,7 +1192,7 @@ export class CodeGenerator {
     } else {
       // Regular methods have a body
       // Handle cases where body might be null or undefined
-      if (!node.value || !node.value.body) {
+      if (!node.value?.body) {
         return this.indent(`${isStatic}${methodName}(${params}) {}`);
       }
       const body = this.generateBlockStatement(node.value.body);

src/config.ts

@@ -174,7 +174,7 @@ function validateModuleSystem(config: unknown, basePath = 'moduleSystem'): Confi
 
 function validateModuleSystemTopLevel(config: object, basePath: string): ConfigValidationError[] {
   const errors: ConfigValidationError[] = [];
-  const knownTop = [
+  const knownTop = new Set([
     'resolution',
     'loading',
     'compilation',
@@ -183,10 +183,10 @@ function validateModuleSystemTopLevel(config: object, basePath: string): ConfigV
     'logger',
     'managementServer',
     'managementPort',
-  ];
+  ]);
 
   for (const key of Object.keys(config)) {
-    if (!knownTop.includes(key)) {
+    if (!knownTop.has(key)) {
       errors.push({ path: `${basePath}.${key}`, message: `unknown property` });
     }
   }

src/core/application-layer.ts

@@ -382,8 +382,6 @@ export class CompilationUseCase implements ICompilationUseCase {
         metrics,
       };
     } catch (error) {
-      const totalTime = performance.now() - startTime;
-
       errors.push({
         message: `Compilation failed: ${error}`,
         line: 0,

src/core/modular-lexer-compatible.ts

@@ -374,7 +374,7 @@ export class OperatorRecognizer extends BaseTokenRecognizer {
   canRecognize(input: string, position: number): boolean {
     const char = this.peek(input, position);
     // Check if any operator starts with this character
-    return this.sortedOperators.some(op => op[0] === char);
+    return this.sortedOperators.some(op => op.startsWith(char));
   }
 
   recognize(

src/lexer.ts

@@ -275,6 +275,20 @@
       return this.nextToken();
     }
 
+    const switchResult = this.handleSwitchCharacters(char, startLine, startColumn);
+    if (switchResult) return switchResult;
+
+    const operatorResult = this.handleComparisonAndBitwiseOperators(char, startLine, startColumn);
+    if (operatorResult) return operatorResult;
+
+    return this.handleLiteralsAndIdentifiers(char, startLine, startColumn);
+  }
+
+  private handleSwitchCharacters(
+    char: string,
+    startLine: number,
+    startColumn: number
+  ): Token | null {
     switch (char) {
       case '+':
         return this.handlePlusOperator();
@@ -311,22 +325,46 @@
         this.line++;
         this.column = 1;
         return this.createToken(TokenType.NEWLINE, '\n', startLine, startColumn);
+      default:
+        return null;
     }
+  }
 
-    if (char === '=') return this.handleEqualOperator(startLine, startColumn);
-    if (char === '!') return this.handleNotOperator(startLine, startColumn);
-    if (char === '<') return this.handleLessThanOperator(startLine, startColumn);
-    if (char === '>') return this.handleGreaterThanOperator(startLine, startColumn);
-    if (char === '&') return this.handleAmpersandOperator(startLine, startColumn);
-    if (char === '|') return this.handlePipeOperator(startLine, startColumn);
-    if (char === '^') return this.handleCaretOperator(startLine, startColumn);
-    if (char === '?') return this.handleQuestionOperator(startLine, startColumn);
-
-    if (char === '~') {
-      this.advance();
-      return this.createToken(TokenType.BITWISE_NOT, '~', startLine, startColumn);
+  private handleComparisonAndBitwiseOperators(
+    char: string,
+    startLine: number,
+    startColumn: number
+  ): Token | null {
+    switch (char) {
+      case '=':
+        return this.handleEqualOperator(startLine, startColumn);
+      case '!':
+        return this.handleNotOperator(startLine, startColumn);
+      case '<':
+        return this.handleLessThanOperator(startLine, startColumn);
+      case '>':
+        return this.handleGreaterThanOperator(startLine, startColumn);
+      case '&':
+        return this.handleAmpersandOperator(startLine, startColumn);
+      case '|':
+        return this.handlePipeOperator(startLine, startColumn);
+      case '^':
+        return this.handleCaretOperator(startLine, startColumn);
+      case '?':
+        return this.handleQuestionOperator(startLine, startColumn);
+      case '~':
+        this.advance();
+        return this.createToken(TokenType.BITWISE_NOT, '~', startLine, startColumn);
+      default:
+        return null;
     }
+  }
 
+  private handleLiteralsAndIdentifiers(
+    char: string,
+    startLine: number,
+    startColumn: number
+  ): Token {
     if (char === '"' || char === "'") {
       return this.readString(char, startLine, startColumn);
     }

src/module-system/module-registry.ts

@@ -424,17 +424,17 @@ export class ModuleRegistry {
     }
 
     // For relative paths, try to find the matching module
-    const possiblePaths = [
+    const possiblePaths = new Set([
       path.resolve(fromDir, specifier),
       path.resolve(fromDir, specifier + '.som'),
       path.resolve(fromDir, specifier + '.js'),
       path.resolve(fromDir, specifier, 'index.som'),
       path.resolve(fromDir, specifier, 'index.js'),
-    ];
+    ]);
 
     // Find a registered module that matches one of the possible paths
     for (const mod of this.modules.values()) {
-      if (possiblePaths.includes(mod.resolvedPath)) {
+      if (possiblePaths.has(mod.resolvedPath)) {
         return mod.id;
       }
     }

src/module-system/module-system.ts

@@ -259,9 +259,8 @@ export class ModuleSystem {
     this.validateResourceLimits(options, errors);
 
     if (errors.length > 0) {
-      throw new Error(
-        `ModuleSystem configuration validation failed:\n${errors.map((e, i) => `  ${i + 1}. ${e}`).join('\n')}`
-      );
+      const formattedErrors = errors.map((e, i) => `  ${i + 1}. ${e}`).join('\n');
+      throw new Error(`ModuleSystem configuration validation failed:\n${formattedErrors}`);
     }
   }
 
@@ -765,7 +764,12 @@ export class ModuleSystem {
 
       const warningInfo =
         compilationResult.warnings.length > 0
-          ? `\n\nWarnings (${compilationResult.warnings.length}):\n${compilationResult.warnings.map((w, i) => `  ${i + 1}. ${w}`).join('\n')}`
+          ? (() => {
+              const formattedWarnings = compilationResult.warnings
+                .map((w, i) => `  ${i + 1}. ${w}`)
+                .join('\n');
+              return `\n\nWarnings (${compilationResult.warnings.length}):\n${formattedWarnings}`;
+            })()
           : '';
 
       const errorMessage = `Bundle process failed with ${compilationResult.errors.length} error(s):\n\n${errorDetails}${warningInfo}`;
@@ -1026,20 +1030,20 @@ export class ModuleSystem {
 
     const watcher = chokidar.watch(Array.from(watchRoots), watchConfig);
 
-    const supportedEvents: ModuleWatchEventType[] = [
+    const supportedEvents = new Set<ModuleWatchEventType>([
       'add',
       'change',
       'unlink',
       'addDir',
       'unlinkDir',
-    ];
+    ]);
 
     watcher.on('all', (event: string, changedPath: string) => {
       if (!options.onChange) {
         return;
       }
 
-      if (!supportedEvents.includes(event as ModuleWatchEventType)) {
+      if (!supportedEvents.has(event as ModuleWatchEventType)) {
         return;
       }
 

src/module-system/prometheus-metrics.ts

@@ -143,7 +143,7 @@
   /**
    * Helper to add a gauge metric
    */
   private addGaugeMetric(
     lines: string[],
     name: string,
     help: string,
@@ -213,7 +213,14 @@
     );
 
     for (const [name, status] of Object.entries(cbStats)) {
-      const stateValue = status.state === 'closed' ? 0 : status.state === 'open' ? 1 : 2;
+      let stateValue: number;
+      if (status.state === 'closed') {
+        stateValue = 0;
+      } else if (status.state === 'open') {
+        stateValue = 1;
+      } else {
+        stateValue = 2;
+      }
       lines.push(`${this.prefix}_circuit_breaker_state{name="${name}"} ${stateValue} ${timestamp}`);
       lines.push(
         `${this.prefix}_circuit_breaker_failures{name="${name}"} ${status.failures} ${timestamp}`

src/module-system/resource-limiter.ts

@@ -2,7 +2,7 @@
  * Production-grade resource limiting and monitoring
  * Prevents memory exhaustion and resource leaks
  */
-import * as process from 'process';
+import * as process from 'node:process';
 
 export interface ResourceLimits {
   /** Maximum heap memory in bytes (default: 1GB) */
@@ -33,7 +33,7 @@ export type ResourceWarningCallback = (_usage: ResourceUsage, _limit: string) =>
 export class ResourceLimiter {
   private readonly limits: Required<ResourceLimits>;
   private checkIntervalId?: ReturnType<typeof setInterval>;
-  private warningCallbacks: ResourceWarningCallback[] = [];
+  private readonly warningCallbacks: ResourceWarningCallback[] = [];
   private moduleCount = 0;
   private fileHandleCount = 0;
 

src/module-system/runtime-config.ts

@@ -2,8 +2,8 @@
  * Runtime configuration and health check system
  * Provides dynamic configuration updates and HTTP management endpoints
  */
-import * as http from 'http';
-import * as url from 'url';
+import * as http from 'node:http';
+import * as url from 'node:url';
 import { ModuleSystemMetrics } from './metrics';
 import { CircuitBreakerManager } from './circuit-breaker';
 import { LoggerFactory, LogLevel } from './logger';

src/module-system/signal-handler.ts

@@ -20,7 +20,7 @@ export interface SignalHandlerOptions {
  * Graceful shutdown manager for production systems
  */
 export class SignalHandler {
-  private handlers: ShutdownHandler[] = [];
+  private readonly handlers: ShutdownHandler[] = [];
   private isShuttingDown = false;
   private readonly shutdownTimeout: number;
   private readonly logger?: SignalHandlerOptions['logger'];

src/module-system/structured-logger.ts

@@ -1,7 +1,7 @@
 /**
  * Structured logging with JSON support and correlation IDs
  */
-import { randomBytes } from 'crypto';
+import { randomBytes } from 'node:crypto';
 
 export interface LogContext {
   correlationId?: string;
@@ -207,7 +207,7 @@ export class StructuredLogger {
  * Global logger factory with structured logging support
  */
 export class StructuredLoggerFactory {
-  private static loggers = new Map<string, StructuredLogger>();
+  private static readonly loggers = new Map<string, StructuredLogger>();
   private static globalOptions: StructuredLoggerOptions = {
     format: process.env.LOG_FORMAT === 'json' ? 'json' : 'text',
     level: (process.env.LOG_LEVEL as LogLevel) || 'info',

src/parser.ts

@@ -83,9 +83,9 @@ export class Parser {
   private tokens: Token[];
   private current: number = 0;
   private errors: string[] = [];
-  private importHandler: ImportHandler;
-  private declarationHandler: DeclarationHandler;
-  private loopHandler: LoopHandler;
+  private readonly importHandler: ImportHandler;
+  private readonly declarationHandler: DeclarationHandler;
+  private readonly loopHandler: LoopHandler;
 
   constructor(tokens: Token[]) {
     this.tokens = tokens;

src/production-validator.ts

@@ -3,8 +3,8 @@
  * Implements AGENTS.md principle: "Fail fast, fail clearly"
  */
 
-import * as fs from 'fs';
-import * as path from 'path';
+import * as fs from 'node:fs';
+import * as path from 'node:path';
 
 export interface ValidationError {
   category: 'environment' | 'permissions' | 'configuration';