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Chrome Timeline Logger

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This logger helps generates a timeline JSON file that's compatible with the Chrome Dev Tools timeline viewer


npm install chrome-timeline-logger


var timeline = require('chrome-timeline-logger');
var builder = new timeline.TimelineBuilder();
// create a Program record 
var programEvent = builder.startEvent("Program");
// do some stuff 
for (index = _i = 0; _i < 10; index = ++_i) {
  // create a TimeStamp record 
  var event = builder.startEvent("TimeStamp", {message: "hi mum " + index + "!"});
  // set the memory useage for this event 
  event.usedHeapSize = process.memoryUsage().heapUsed;
  // demonstrates how to set the documents count in the counters section 
  event.counters = { documents: index }
  console.log("some work load");
  // end the TimeStamp record 
// end the Program record 
var logger = new timeline.TimelineLogger();"./test.json", programEvent);
  • Best way to discover supported events and their data is to make a recording in the timeline tool and examine it's output ;)
  • I've also made an attempt to list them here TimelineRecordTypes

Above Example Output



name type args description
save() method string filepath, timelineRecordList[], onComplete() saves an array of timeline records to a file specified by the filepath
saveSync() method string filepath, timelineRecordList[] Synchronous version of save
version string Appears at the top of each saved timeline json file
name type args description
startEvent() method string type, [object data] starts a timeline event. Types are defined in TimelineRecordTypes
endEvent() method none ends the currently started timeline event.
name type args description
start() method none sets startTime to
end() method none sets endTime to
startTime number
endTime number
children TimelineRecord[]
data object
frameId number
usedHeapSize number
usedHeapSizeDelta number
counters object
stackTrace object


You can discover the history inside the file


You can discover the contributing instructions inside the file


Licensed under the incredibly permissive MIT License
Copyright © 2013+ Stringz Solutions Ltd
Copyright © 2013+ Peter Flannery