Log a warning when in development mode

Do you want to request a feature or report a bug?

• feature

Ref this tweet from Dan - https://twitter.com/dan_abramov/status/775647965197336576

It’s currently too easy to use React in development mode while in production, and there’s little warning from the library that this is happening. Further, it takes a fair bit of googling to know what to do, (it’s tucked away under ‘advanced performance’ in the docs, and doesn’t include directions for webpack/browserify).

As a start, I recommend that react always log a message to console when it’s in development mode. Something like -

“running in development mode, use production mode flags to speed up your code”

This stands out, and I hope will prevent some, if not most, of these misses.