profilerBase.ts

utils/profilerBase.ts

file-tools

Lines

1572

Bytes

Exports

Imports

Keywords

What this is

This page documents one file from the repository and includes its full source so you can read it without leaving the docs site.

Beginner explanation

This file is one piece of the larger system. Its name, directory, imports, and exports show where it fits. Start by reading the exports and related files first.

How it is used

Start from the exports list and related files. Those are the easiest clues for where this file fits into the system.

Expert explanation

Architecturally, this file intersects with file-tools. It contains 47 lines, 2 detected imports, and 3 detected exports.

Important relationships

Detected exports

getPerformance
formatMs
formatTimelineLine

Keywords

performanceperf_hooksmemorysharedformatperformancetypeformatfilesizeformatmsnameextra

Detected imports

perf_hooks
./format.js

Source notes

This page embeds the full file contents. Small or leaf files are still indexed honestly instead of being over-explained.

Open parent directory

Full source

/**
 * Shared infrastructure for profiler modules (startupProfiler, queryProfiler,
 * headlessProfiler). All three use the same perf_hooks timeline and the same
 * line format for detailed reports.
 */

import type { performance as PerformanceType } from 'perf_hooks'
import { formatFileSize } from './format.js'

// Lazy-load performance API only when profiling is enabled.
// Shared across all profilers — perf_hooks.performance is a process-wide singleton.
let performance: typeof PerformanceType | null = null

export function getPerformance(): typeof PerformanceType {
  if (!performance) {
    // eslint-disable-next-line @typescript-eslint/no-require-imports
    performance = require('perf_hooks').performance
  }
  return performance!
}

export function formatMs(ms: number): string {
  return ms.toFixed(3)
}

/**
 * Render a single timeline line in the shared profiler report format:
 *   [+  total.ms] (+  delta.ms) name [extra] [| RSS: .., Heap: ..]
 *
 * totalPad/deltaPad control the padStart width so callers can align columns
 * based on their expected magnitude (startup uses 8/7, query uses 10/9).
 */
export function formatTimelineLine(
  totalMs: number,
  deltaMs: number,
  name: string,
  memory: NodeJS.MemoryUsage | undefined,
  totalPad: number,
  deltaPad: number,
  extra = '',
): string {
  const memInfo = memory
    ? ` | RSS: ${formatFileSize(memory.rss)}, Heap: ${formatFileSize(memory.heapUsed)}`
    : ''
  return `[+${formatMs(totalMs).padStart(totalPad)}ms] (+${formatMs(deltaMs).padStart(deltaPad)}ms) ${name}${extra}${memInfo}`
}