chore: add vendored numeric-separators-style ESLint rule

eslint.config.js

@@ -6,6 +6,8 @@ import { defineConfig } from 'eslint/config';
 import globals from 'globals';
 import tseslint from 'typescript-eslint';
 
+import numericSeparatorsPlugin from './vendor/eslint-numeric-separators-style/index.js';
+
 // TODO: setup eslint-plugin-n
 export default defineConfig(
   jsPlugin.configs.recommended,
@@ -25,6 +27,7 @@ export default defineConfig(
     plugins: {
       '@perfectionist': perfectionist,
       '@stylistic': stylistic,
+      'numeric-separators': numericSeparatorsPlugin,
     },
     rules: {
       '@perfectionist/sort-classes': ['error', { partitionByNewLine: true }],
@@ -42,7 +45,6 @@ export default defineConfig(
       ],
       '@stylistic/lines-between-class-members': ['error', 'always'],
       '@stylistic/semi': 'error',
-
       '@typescript-eslint/consistent-type-exports': [
         'error',
         { fixMixedExportsWithInlineTypeSpecifier: true },
@@ -92,9 +94,9 @@ export default defineConfig(
 
       // these 6 bytes add up
       '@typescript-eslint/require-await': 'off',
+
       // I like my template expressions, tyvm
       '@typescript-eslint/restrict-template-expressions': 'off',
-
       '@typescript-eslint/unified-signatures': [
         'error',
         {
@@ -111,6 +113,7 @@ export default defineConfig(
       'no-constructor-return': 'error',
 
       'no-empty': ['error', { allowEmptyCatch: true }],
+
       'no-restricted-syntax': [
         'error',
         {
@@ -121,6 +124,7 @@ export default defineConfig(
         },
       ],
       'no-self-compare': 'error',
+      'numeric-separators/numeric-separators-style': 'error',
       'object-shorthand': ['error', 'always'],
       'prefer-arrow-callback': 'error',
       semi: 'error',

examples/bench/performance-tips.bench.js

@@ -29,7 +29,7 @@ export default {
       benchmarks: {
         // Fast operations need more iterations
         'Array Access': {
-          config: { iterations: 10000 },
+          config: { iterations: 10_000 },
           fn: () => iterationState.smallArray[50],
           tags: ['fast', 'array'],
         },
@@ -46,7 +46,7 @@ export default {
         iterationState.smallArray = Array.from({ length: 100 }, (_, i) => i);
         iterationState.largeComputation = () => {
           let result = 0;
-          for (let i = 0; i < 100000; i++) {
+          for (let i = 0; i < 100_000; i++) {
             result += Math.sqrt(i);
           }
           return result;
@@ -84,7 +84,7 @@ export default {
 
       setup: () => {
         // Generate large dataset once for all benchmarks
-        optimizationState.dataset = Array.from({ length: 10000 }, (_, i) => ({
+        optimizationState.dataset = Array.from({ length: 10_000 }, (_, i) => ({
           id: i,
           name: `item-${i}`,
           value: Math.random(),

examples/profiling-demo.js

@@ -9,7 +9,7 @@
 
 // Medium function - string manipulation
 const parseAndFormat = () => {
-  const data = Array.from({ length: 100000 }, (_, i) => {
+  const data = Array.from({ length: 100_000 }, (_, i) => {
     const raw = `${i}|item-${i}|${Math.random() * 100}`;
     const parts = raw.split('|');
     return {
@@ -23,7 +23,7 @@ const parseAndFormat = () => {
 
 // Warm function - moderate CPU time
 const processStrings = () => {
-  const strings = Array.from({ length: 500000 }, (_, i) => `item-${i}`);
+  const strings = Array.from({ length: 500_000 }, (_, i) => `item-${i}`);
   return strings
     .map((s) => s.toUpperCase())
     .filter((s) => s.includes('5'))
@@ -32,7 +32,7 @@ const processStrings = () => {
 
 // Medium-warm function - JSON serialization
 const serializeData = () => {
-  const data = Array.from({ length: 50000 }, (_, i) => ({
+  const data = Array.from({ length: 50_000 }, (_, i) => ({
     id: i,
     metadata: { created: Date.now(), updated: Date.now() },
     name: `Record ${i}`,
@@ -48,13 +48,13 @@ const simpleCalculation = () => {
 
 // Hot function - lots of CPU time
 const sortLargeArray = () => {
-  const arr = Array.from({ length: 1000000 }, () => Math.random());
+  const arr = Array.from({ length: 1_000_000 }, () => Math.random());
   return arr.sort((a, b) => a - b);
 };
 
 // Warm function - object manipulation
 const transformData = () => {
-  const data = Array.from({ length: 200000 }, (_, i) => ({
+  const data = Array.from({ length: 200_000 }, (_, i) => ({
     id: i,
     name: `Item ${i}`,
     value: Math.random() * 100,
@@ -72,7 +72,7 @@ const transformData = () => {
 // Another hot function - regex processing
 const validateEmails = () => {
   const emails = Array.from(
-    { length: 100000 },
+    { length: 100_000 },
     (_, i) => `user${i}@example.com`,
   );
   const regex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
@@ -111,7 +111,7 @@ validateEmails();
 transformData();
 
 console.log('Simple calculations (cold path)...');
-for (let i = 0; i < 10000; i++) {
+for (let i = 0; i < 10_000; i++) {
   simpleCalculation();
 }
 

src/cli/commands/baseline.ts

@@ -69,13 +69,13 @@ const formatDuration = (nanoseconds: number): string => {
   if (nanoseconds < 1000) {
     return `${nanoseconds.toFixed(2)}ns`;
   }
-  if (nanoseconds < 1000000) {
+  if (nanoseconds < 1_000_000) {
     return `${(nanoseconds / 1000).toFixed(2)}μs`;
   }
-  if (nanoseconds < 1000000000) {
-    return `${(nanoseconds / 1000000).toFixed(2)}ms`;
+  if (nanoseconds < 1_000_000_000) {
+    return `${(nanoseconds / 1_000_000).toFixed(2)}ms`;
   }
-  return `${(nanoseconds / 1000000000).toFixed(2)}s`;
+  return `${(nanoseconds / 1_000_000_000).toFixed(2)}s`;
 };
 
 /**
@@ -85,13 +85,13 @@ const formatOpsPerSec = (ops: number): string => {
   if (ops < 1000) {
     return `${ops.toFixed(2)} ops/sec`;
   }
-  if (ops < 1000000) {
+  if (ops < 1_000_000) {
     return `${(ops / 1000).toFixed(2)}K ops/sec`;
   }
-  if (ops < 1000000000) {
-    return `${(ops / 1000000).toFixed(2)}M ops/sec`;
+  if (ops < 1_000_000_000) {
+    return `${(ops / 1_000_000).toFixed(2)}M ops/sec`;
   }
-  return `${(ops / 1000000000).toFixed(2)}B ops/sec`;
+  return `${(ops / 1_000_000_000).toFixed(2)}B ops/sec`;
 };
 
 /**

src/cli/commands/init.ts

@@ -51,7 +51,7 @@ const PROJECT_TEMPLATES = {
       outputDir: DEFAULT_OUTPUT_DIR,
       pattern: `${DEFAULT_BENCHMARK_DIR}/**/*.bench.{js,ts}`,
       reporters: ['human', 'json'],
-      time: 10000,
+      time: 10_000,
       warmup: 50,
     },
     description: 'Feature-rich setup with multiple reporters and configuration',
@@ -77,7 +77,7 @@ const PROJECT_TEMPLATES = {
       outputDir: DEFAULT_OUTPUT_DIR,
       pattern: `${DEFAULT_BENCHMARK_DIR}/**/*.bench.{js,ts}`,
       reporters: ['human', 'json'],
-      time: 15000,
+      time: 15_000,
       warmup: 100,
     },
     description: 'Optimized for library performance testing',

src/cli/commands/test.ts

@@ -55,7 +55,7 @@ const getDefaultTestConfig = (
   tags: [],
   thresholds: {},
   time: 1000,
-  timeout: 30000,
+  timeout: 30_000,
   verbose,
   warmup,
 });

src/config/budget-schema.ts

@@ -26,7 +26,7 @@ export const parseTimeString = (value: string): number => {
     ms: 1_000_000,
     ns: 1,
     s: 1_000_000_000,
-    us: 1_000,
+    us: 1000,
   };
 
   return num * multipliers[unit as keyof typeof multipliers];

src/core/engines/accurate-engine.ts

@@ -38,7 +38,7 @@ export class AccurateEngine extends ModestBenchEngine {
    * Maximum iterations per round to prevent overwhelming Node.js test runner
    * and excessive memory usage
    */
-  private static readonly MAX_ITERATIONS_PER_ROUND = 10000;
+  private static readonly MAX_ITERATIONS_PER_ROUND = 10_000;
 
   /**
    * Maximum iterations per round for async functions (much lower due to

src/formatters/history/compare.ts

@@ -51,8 +51,8 @@ export class HistoryCompareFormatter implements HistoryFormatter<CompareResult>
       lines.push('');
 
       for (const comparison of data.tasksInBoth) {
-        const mean1 = comparison.run1!.mean / 1000000; // Convert to ms
-        const mean2 = comparison.run2!.mean / 1000000;
+        const mean1 = comparison.run1!.mean / 1_000_000; // Convert to ms
+        const mean2 = comparison.run2!.mean / 1_000_000;
         const changeSign = comparison.percentChange >= 0 ? '+' : '';
         const changeStr = `${changeSign}${comparison.percentChange.toFixed(1)}%`;
 
@@ -73,8 +73,8 @@ export class HistoryCompareFormatter implements HistoryFormatter<CompareResult>
         );
 
         // Min - highlight higher number
-        const min1 = comparison.run1!.min / 1000000;
-        const min2 = comparison.run2!.min / 1000000;
+        const min1 = comparison.run1!.min / 1_000_000;
+        const min2 = comparison.run2!.min / 1_000_000;
         const minHigher = min2 > min1;
         const min1Str = minHigher
           ? colorize('magenta', `${min1.toFixed(3)}ms`)
@@ -87,8 +87,8 @@ export class HistoryCompareFormatter implements HistoryFormatter<CompareResult>
         );
 
         // Max - highlight higher number
-        const max1 = comparison.run1!.max / 1000000;
-        const max2 = comparison.run2!.max / 1000000;
+        const max1 = comparison.run1!.max / 1_000_000;
+        const max2 = comparison.run2!.max / 1_000_000;
         const maxHigher = max2 > max1;
         const max1Str = maxHigher
           ? colorize('magenta', `${max1.toFixed(3)}ms`)

src/formatters/history/show.ts

@@ -148,8 +148,8 @@ const formatTime = (ns: number): string => {
   if (ns < 1000) {
     return `${ns.toFixed(2)}ns`;
   }
-  if (ns < 1000000) {
+  if (ns < 1_000_000) {
     return `${(ns / 1000).toFixed(3)}µs`;
   }
-  return `${(ns / 1000000).toFixed(3)}ms`;
+  return `${(ns / 1_000_000).toFixed(3)}ms`;
 };

src/formatters/history/trends.ts

@@ -24,7 +24,7 @@ const NS_PER_MS = 1_000_000;
 /**
  * Nanoseconds per microsecond conversion constant
  */
-const NS_PER_US = 1_000;
+const NS_PER_US = 1000;
 
 /**
  * Intelligently format a time range with appropriate precision Displays

src/reporters/human.ts

@@ -234,7 +234,7 @@ export class HumanReporter extends BaseReporter {
       );
     }
     this.printLine(
-      `${this.colorize('cyan', ansiChars.approx + ' Duration:')} ${this.colorize('brightWhite', BaseReporter.formatDuration(duration * 1000000))}`,
+      `${this.colorize('cyan', ansiChars.approx + ' Duration:')} ${this.colorize('brightWhite', BaseReporter.formatDuration(duration * 1_000_000))}`,
     );
     this.printLine();
 
@@ -463,7 +463,7 @@ export class HumanReporter extends BaseReporter {
       });
 
       const durationStr = BaseReporter.formatDuration(
-        result.duration * 1000000,
+        result.duration * 1_000_000,
       );
 
       // Display suite setup failure
@@ -487,7 +487,9 @@ export class HumanReporter extends BaseReporter {
     const passed = result.tasks.filter((t) => !t.error && !t.aborted).length;
     const failed = result.tasks.filter((t) => t.error).length;
     const aborted = result.tasks.filter((t) => t.aborted).length;
-    const durationStr = BaseReporter.formatDuration(result.duration * 1000000); // ms to ns
+    const durationStr = BaseReporter.formatDuration(
+      result.duration * 1_000_000,
+    ); // ms to ns
 
     // Build summary parts
     const parts: string[] = [];

src/reporters/nyan.ts

@@ -345,7 +345,7 @@ export class NyanReporter extends BaseReporter {
    */
   private printEpilogue(run: BenchmarkRun): void {
     const duration = Date.now() - this.startTime;
-    const durationStr = BaseReporter.formatDuration(duration * 1000000);
+    const durationStr = BaseReporter.formatDuration(duration * 1_000_000);
 
     console.log();
     console.log(

src/services/budget-evaluator.ts

@@ -37,10 +37,10 @@ export class BudgetEvaluator {
    * Format time in nanoseconds to human-readable string
    */
   private static formatTime(this: void, nanoseconds: number): string {
-    if (nanoseconds < 1_000) {
+    if (nanoseconds < 1000) {
       return `${nanoseconds.toFixed(0)}ns`;
     } else if (nanoseconds < 1_000_000) {
-      return `${(nanoseconds / 1_000).toFixed(2)}μs`;
+      return `${(nanoseconds / 1000).toFixed(2)}μs`;
     } else if (nanoseconds < 1_000_000_000) {
       return `${(nanoseconds / 1_000_000).toFixed(2)}ms`;
     } else {

src/services/config-manager.ts

@@ -63,7 +63,7 @@ const DEFAULT_CONFIG: ModestBenchConfig = {
   tags: [],
   thresholds: {},
   time: 1000, // 1 second minimum for tinybench to gather samples
-  timeout: 30000, // 30 seconds
+  timeout: 30_000, // 30 seconds
   verbose: false, // No verbose output by default
   warmup: 30, // Light warmup by default - enough for basic JIT optimization
 };
@@ -291,7 +291,7 @@ export class ModestBenchConfigurationManager implements ConfigurationManager {
       }
 
       // Warn about potentially long runtime
-      if (validConfig.iterations > 1000 && validConfig.time > 60000) {
+      if (validConfig.iterations > 1000 && validConfig.time > 60_000) {
         warnings.push({
           code: 'LONG_RUNTIME_WARNING',
           file: 'configuration',

src/services/reporter-registry.ts

@@ -39,12 +39,12 @@ export abstract class BaseReporter implements Reporter {
   protected static formatDuration(this: void, nanoseconds: number): string {
     if (nanoseconds < 1000) {
       return `${nanoseconds.toFixed(2)}ns`;
-    } else if (nanoseconds < 1000000) {
+    } else if (nanoseconds < 1_000_000) {
       return `${(nanoseconds / 1000).toFixed(2)}μs`;
-    } else if (nanoseconds < 1000000000) {
-      return `${(nanoseconds / 1000000).toFixed(2)}ms`;
+    } else if (nanoseconds < 1_000_000_000) {
+      return `${(nanoseconds / 1_000_000).toFixed(2)}ms`;
     } else {
-      return `${(nanoseconds / 1000000000).toFixed(2)}s`;
+      return `${(nanoseconds / 1_000_000_000).toFixed(2)}s`;
     }
   }
 
@@ -57,12 +57,12 @@ export abstract class BaseReporter implements Reporter {
   ): string {
     if (opsPerSecond < 1000) {
       return `${opsPerSecond.toFixed(2)} ops/sec`;
-    } else if (opsPerSecond < 1000000) {
+    } else if (opsPerSecond < 1_000_000) {
       return `${(opsPerSecond / 1000).toFixed(2)}K ops/sec`;
-    } else if (opsPerSecond < 1000000000) {
-      return `${(opsPerSecond / 1000000).toFixed(2)}M ops/sec`;
+    } else if (opsPerSecond < 1_000_000_000) {
+      return `${(opsPerSecond / 1_000_000).toFixed(2)}M ops/sec`;
     } else {
-      return `${(opsPerSecond / 1000000000).toFixed(2)}B ops/sec`;
+      return `${(opsPerSecond / 1_000_000_000).toFixed(2)}B ops/sec`;
     }
   }
 

test/fixtures/config/test-config.js

@@ -20,7 +20,7 @@ export default {
     maxMean: 1000,
   },
   time: 2000,
-  timeout: 60000,
+  timeout: 60_000,
   verbose: true,
   warmup: 100,
 };

test/fixtures/config/test-config.ts

@@ -22,7 +22,7 @@ const config: Partial<ModestBenchConfig> = {
     maxMean: 1000,
   },
   time: 2000,
-  timeout: 60000,
+  timeout: 60_000,
   verbose: true,
 
   warmup: 100,