let supported: boolean let perf: Performance export function isPerformanceSupported() { if (supported !== undefined) { return supported } if (typeof window !== 'undefined' && window.performance) { supported = true perf = window.performance } else if (typeof globalThis !== 'undefined' && (globalThis as any).perf_hooks?.performance) { supported = true perf = (globalThis as any).perf_hooks.performance } else { supported = false } return supported } export function now() { return isPerformanceSupported() ? perf.now() : Date.now() }