| import { PerformanceObserver } from 'perf_hooks' | |
| import { warn } from '../../build/output/log' | |
| import { bold } from '../picocolors' | |
| const LONG_RUNNING_GC_THRESHOLD_MS = 15 | |
| const gcEvents: PerformanceEntry[] = [] | |
| const obs = new PerformanceObserver((list) => { | |
| const entry = list.getEntries()[0] | |
| gcEvents.push(entry) | |
| if (entry.duration > LONG_RUNNING_GC_THRESHOLD_MS) { | |
| warn(bold(`Long running GC detected: ${entry.duration.toFixed(2)}ms`)) | |
| } | |
| }) | |
| /** | |
| * Starts recording garbage collection events in the process and warn on long | |
| * running GCs. To disable, call `stopObservingGc`. | |
| */ | |
| export function startObservingGc() { | |
| obs.observe({ entryTypes: ['gc'] }) | |
| } | |
| export function stopObservingGc() { | |
| obs.disconnect() | |
| } | |
| /** | |
| * Returns all recorded garbage collection events. This function will only | |
| * return information from when `startObservingGc` was enabled and before | |
| * `stopObservingGc` was called. | |
| */ | |
| export function getGcEvents() { | |
| return gcEvents | |
| } | |