通过在React中使用循环来使用setstate

Question

I have two array of objects. I want to setState of an variable by looping through this two arrays.

I have a state ,

this.state = {  selectedValue: {} }

I have this two array of objects ,

this.props.untracked.content && `this.props.tracked.content`

What I did to setstate is ,

this.setState({
        selectedValue: {
          ...this.state.selectedValue,
          [`${resumeId}`]: type
        }
      }

In another place where I was not required to loop . Now I need to loop through this two and then I need to setState,

for loop I did ,

for (const item of 

[...this.props.untracked.content,...this.props.tracked.content]) {
    this.setState({
     selectedValue: {
          ...this.state.selectedValue,
          [`${item.id}`]: item.value
        }
})    
}

So, Can any one help me with this ? Thanks.

Answer 1

要做到这一点，最简单的方法是做所有的处理没有setState和使用setState一次底。

Answer 2

Use setState(oldState => newState) when new state depends on the current one:

this.setState(oldState => ({
     selectedValue: {
          ...oldState.selectedValue,
          [`${item.id}`]: item.value
     }
}));

Also it is better to prepare all updates beforehand:

const updates = {};
for (const item of 
    [...this.props.untracked.content,...this.props.tracked.content]
) {
    updates[item.id] = item.value;
}

this.setState(oldState => ({
     selectedValue: {
          ...oldState.selectedValue,
          ...updates,
     }
}));