import { inBrowser } from './env' export let mark export let measure if (process.env.NODE_ENV !== 'production') { const perf = inBrowser && window.performance /* istanbul ignore if */ if ( perf && perf.mark && perf.measure && perf.clearMarks && perf.clearMeasures ) { mark = tag => perf.mark(tag) measure = (name, startTag, endTag) => { perf.measure(name, startTag, endTag) perf.clearMarks(startTag) perf.clearMarks(endTag) // perf.clearMeasures(name) } } }