@jsenv/performance-impact analyses a pull request impact on your performance metrics. This analysis is posted in a comment of the pull request on GitHub.
- Helps you to catch big performance variations before merging a pull request
- Gives you the ability to measure performances on your machine during dev
- Can be added to any automated process (GitHub workflow, Jenkins, ...)
Disclaimer: This tool should not be used to catch small performance variations because they are hard to distinguish from the natural variations of performance metrics (see performance variability).
Screenshot of a pull request comment
Performance metrics will change due to inherent variability, even if there hasn't been a code change. It can be mitigated by measuring performance multiple times. But you should always keep in mind this variability before drawing conclusions about a performance-impacting change.
With time you'll be capable to recognize unusual variation in your performance metrics.
Catching (very) small performance impacts with confidence requires repetition and time. You need to:
-
Let your code be used a lot of times in a lot of scenarios and see the results. This could be scripts, real users or both.
-
And or push your performance metrics in a tool like Kibana or DataDog and check the tendency of your performance metrics.
In any case it means you have to wait before knowing the real performance impact.
- measure some performance metrics
- Big variations can be anticipated and catched by
@jsenv/performance-impact - For small variations, upload performance metrics to a dashboard. Then, periodically watch the dashboard to check performance metrics tendency over time