Neither this comment nor the article clearly spell this out: when you use the production version of React, much of the developer-assisting error checking is rem

Neither this comment nor the article clearly spell this out: when you use the production version of React, much of the developer-assisting error checking is removed (not just propTypes[1], but many other error checks[2]), so you don't need to worry about the end-user performance impact of propTypes. As an example of how much this helps, one React-heavy page of mine dropped from 1500ms to 300ms by switching versions, according to my browser profiler. [1] https://facebook.github.io/react/docs/reusable-components.html#prop-validation https://facebook.github.io/react/docs/reusable-components.ht... [2] https://facebook.github.io/react/downloads.html#development-vs.-production-builds https://facebook.github.io/react/downloads.html#development-...