Interface PerformanceSnapshot

Current browser performance metrics and retained histories.

interface PerformanceSnapshot {
    cls: number;
    fps: number;
    fpsHistory: number[];
    longTasks: LongTaskInfo;
    memory: MemoryInfo | null;
    memoryHistory: number[];
}

Properties

cls: number

Cumulative Layout Shift value collected from layout-shift performance entries.

fps: number

Latest frames-per-second measurement.

fpsHistory: number[]

Recent FPS measurements, capped by maxHistory.

Long task counter and last observed duration.

memory: MemoryInfo | null

Current heap memory information, or null outside browsers that expose performance.memory.

memoryHistory: number[]

Recent memory usage percentages, capped by maxHistory.