// page/index/index
Page({
    onLoad() {
        // 假如业务方想统计fp、fcp、fmp
        const performance = xhs.getPerformance()
        this.observer = performance.createObserver((entryList) => {
                const entries = entryList.getEntries()
                this.report(entries)
          })
        this.observer.observe({ entryTypes: ['paint'] })
        // or this.observer.observe({ type: 'paint' })
    },
 
 
    report(entries) {
        const fp = entries.filter(item => item.name === 'firstPaint')[0]
        if (fp) {
            const { 
                startTime, // fp的时间戳
                duration,  // 无
                value,  // performance.timing.navigationStart - startTime的这段时间
             } = fp
        }
        // 业务方do something
     },
 
    onUnload() {
        this.observer.disconnect()
    }
})