const puppeteer = require('puppeteer'); const tracealyzer = require('tracealyzer'); const TRACE_FILE = 'test/data/trace.json'; (async () => { const browser = await puppeteer.launch(); const page = await browser.newPage(); await page.tracing.start({path: TRACE_FILE}); await page.goto('https://www.wired.com'); await page.tracing.stop(); await browser.close(); const metrics = tracealyzer(TRACE_FILE); // do something with fx. metrics.rendering.fps.mean })(); 

{ "rendering": { "firstPaint": 0.031781, "forcedReflowEvents": 82, "fps": { "mean": 8.94, "variance": 1599518.62, "sd": 1264.72, "lo": 2, "hi": 9345.79 } }, "profiling": { "categories": { "scripting": 2477.3910000920296, "rendering": 440.5760000050068, "loading": 261.3550000190735, "painting": 83.19600003957748 }, "events": { "JS Frame": 2014.1029999256134, "Recalculate Style": 308.1180000901222, "Compile Script": 223.743999928236, "Parse HTML": 206.10900002717972, "DOM GC": 113.408999979496, "Minor GC": 88.0469999909401, "Layout": 64.36799997091293, "Parse Stylesheet": 55.24599999189377, "Update Layer Tree": 53.366999953985214, "Paint": 46.88600006699562, "Composite Layers": 36.30999997258186, "Evaluate Script": 20.951000213623047, "Hit Test": 14.72299998998642, "Major GC": 9.86200001835823, "Run Microtasks": 7.10699999332428, "XHR Ready State Change": 0.13700002431869507, "XHR Load": 0.03100001811981201 }, "functions": { "f:send@0": 781.0239999890327, "UpdateLayoutTree": 308.1180000901222, "v8.compile": 223.743999928236, "ParseHTML": 206.10900002717972, "f:addSelectors@497": 126.76800009608269, "MinorGC": 88.0469999909401, "f:insertRule@0": 87.70299994945526, "ThreadState::completeSweep": 82.5949999988079, "Layout": 64.36799997091293, "ParseAuthorStyleSheet": 55.24599999189377, "UpdateLayerTree": 53.366999953985214, "Paint": 46.88600006699562, "f:@479": 37.90599998831749, "CompositeLayers": 36.30999997258186, "f:GetGlobal@0": 29.496999949216843, "f:@499": 27.094000041484833, "BlinkGCMarking": 26.229999989271164, "f:exec@0": 25.107000023126602, "f:@503": 23.692999929189682, "f:@536": 23.41399994492531, "EvaluateScript": 20.951000213623047, "f:Apply@0": 20.906999975442886, "f:join@6": 19.371999979019165 }, "userFunctions": { "f:send@0": 781.0239999890327, "f:addSelectors@497": 126.76800009608269, "f:insertRule@0": 87.70299994945526, "f:GetGlobal@0": 29.496999949216843, "f:exec@0": 25.107000023126602, "f:Apply@0": 20.906999975442886, "f:join@6": 19.371999979019165, "f:dispatchOnMessage@487": 15.487000048160553, "f:generate@479": 11.16499999165535, "f:appendChild@0": 10.810000032186508, "f:Z@540": 10.56799989938736, "f:getItem@0": 8.602999985218048, "f:s@517": 8.28099998831749, "f:Ug@521": 8.250999987125397, "f:P_@536": 7.683999985456467, "f:each@503": 7.172000020742416 } } }