In a previous lesson, they say you can change the state
by passing an object to the setState
method, but now they jumped to functions, can someone explain more please! and why we shouldn’t use this in this lesson, thank you in advance!
Hi @bedward.
The reason of passing a callback to setState
is right there in the explanation. React state updates can sometimes occur asynchronously.
Sometimes you might need to know the previous state when updating the state. However, state updates may be asynchronous - this means React may batch multiple
setState()
calls into a single update. This means you can’t rely on the previous value ofthis.state
orthis.props
when calculating the next value. So, you should not use code like this:
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