React调用在无状态组件的props中传递的调用setState的函数

Question

I am working on filter component being made with React.JS. A few of those filtering components are embedded in a panel ( div ). The wrapping parts of the panel look like the below:

        Initiative <a onClick={() => {this.setState({ showInitiatives: true })}} className="milestone-list-link" href="#initiative">
          {this.state.selectedInitiative}
          <InitiativeSelector
            initiatives={initiatives || {}}
            show={this.state.showInitiatives}
            selector={
              () => {
                console.log('called selector state:', this.state)
                this.setState({ showInitiatives: false })
              }
            }
          />
          <FilterIcon />
        </a>

My <InitiativeSelector /> looks like the below:

const InitiativeSelector = ({initiatives, show, selector}) => {
  return (show) ? (
    <div className="list-filter">
      <div>
        <input placeholder="Search..." />
      </div>
      <ul>
        {
          Object.values(initiatives).map((initiative, i) => <li onClick={() => {selector()}} key={i}>{initiative.name}</li> )
        }  
      </ul>
    </div>
  ) : null
}

When I run this, my selector does get called. Hence, I see state printed to the console. However, this.setState({ showInitiatives: false }) does not seem to do anything. My modal does not hide, and the second (etc) time I click on the <li> , showInitiatives still set to true .

Answer 1

This is because click event bubbles up the DOM tree combined with async nature of setState

First li.onClick fires calling selector which calls setState({ showInitiatives: false})

Then a.onClick fires calling setState({ showInitiatives: true }) . You could check it is true say by adding log statement to it.

Now you have 2 pending updates

{ showInitiatives: false}
{ showInitiatives: true}

which when merged is noop.

You need to either stop event propagation inside li.onClick by calling e.stopPropagation() or rethink what a.onClick handler is doing.