Trace-event-lib NPM

trace-event-lib

A library to create a trace of your JS app per Google's Trace Event format.

chrome://tracing example

These logs can then be visualized with:

chrome://tracing (see the archive)
Perfetto – doesn't support async events, as of 29.06.2022.

Install

npm install trace-event-lib --save

Usage

import { AbstractEventBuilder } from 'chrome-trace-event';

class ConcreteEventBuilder extends AbstractEventBuilder {
    send(event) {
        // Implement the abstract method: push events into a stream, array, etc.
    }
}

const trace = new ConcreteEventBuilder();

trace.begin({ cat: 'category1,category2', name: 'duration event' });
// ...
trace.instant({ name: 'resolve config', args: { /* ... */ } });
// ...
trace.complete({ name: 'nested event', dur: 3e6 /* 3s */ });
// ...
trace.end();

/**
 * Also, see the other methods on the website.
 *
 * @see {@link AbstractEventBuilder#beginAsync}
 * @see {@link AbstractEventBuilder#instantAsync}
 * @see {@link AbstractEventBuilder#endAsync}
 * @see {@link AbstractEventBuilder#counter}
 * @see {@link AbstractEventBuilder#metadata}
 * @see {@link AbstractEventBuilder#process_name}
 * @see {@link AbstractEventBuilder#process_labels}
 * @see {@link AbstractEventBuilder#process_sort_index}
 * @see {@link AbstractEventBuilder#thread_name}
 * @see {@link AbstractEventBuilder#thread_sort_index}
 */