facebook/react — pull request #2303 by sebmarkbage (2014-10-07 23:48:54+00:00)
Title: Use Object.assign instead of merge, mergeInto, mixInto and copyPropertie...

...s

This makes it easier to contribute without having to learn a bunch of
slightly different helpers and remember their slightly different
signatures and semantics.

We'll probably start using ES7 spread properties instead of merge in the
future when at least one more transpiler supports it.