javascript - Why is part of setState assigned to state, but part of it cannot be assigned?

Question

nextProps is assigned to state, but what’s wrong with the subsequent totalCount assignment that doesn’t go in?

totalCount is still the initial value 0

Answer 1

The way is wrong, the second parameter of setState is a function.
I guess you want to write it like this,

this.setState({
...nextProps,
totalCount: totalCount
})

But I don’t understand why I need to props 放到 state. Is there any other operation?

Answer 2

Where did you learn this usage of setState from?

setState

Answer 3

void setState(
  function|object nextState,
  [function callback]
)
第一个参数是要改变的state参数，第二个是回调函数

Answer 4

Thanks for the invitation, actually I haven’t written react for a long time....

The signature of setState is like this
setState(nextState: object | function, callback?: function)
Only accepts the first parameter as nextState, and the second parameter is the callback after setState ends and is re-rendered

And your code has too many flaws
Just to traverse and calculate totalPrice and totalCount, you should use _.each instead of _.map
And set the props to state. What is this going to do...