javascript - How to change a react state immediately by setTimeout after setState? -


new in react here, don't know if it's right on setstate callback this?

           settimeout(()=> {             this.setstate((state, props) => ({ activatelightcolorforred: true }), () => {               settimeout(()=> {                 this.setstate(()=> ({ activatelightcolorforred: false }))               }, 500);               red.play();             })           }, towait);

or maybe this?

 this.setstate((state, props) => {     this.setstate((state, props) => {       activatelightcolorforred: true     });     settimeout(() => { activatelightcolorforred: false },500)   })

are state on setstate callback updated? weird happening in components, it's rendering multiple times. not sure think it's because i'm doing first sample?

your question not seem follow pattern of regular react app. should using lifecycle events react state being changed. should not making multiple, nested, confusing callbacks (like seems want do).

might suggest structure more this

class foo extends component {     constructor(props) {         super(props);         this.state = {             activatelightcolorforred: false,         };         this.turnlightred = () => {            // function turn light red            this.setstate(() => ({ activatelightcolorforred: true });         }     }     componentdidupdate(nextprops, nextstate) {        if (nextstate.activatelightcolorforred) {           // when state updated (turned red),            // timeout triggered switch off           this.turnoffredtimeout = settimeout(() => {                this.setstate(() => ({activatelightcolorforred: false})           }, 500);        }     }     componentwillunmount() {         // set timeout this.turnoffredtimeout can         // clean when component unmounted.         // otherwise app trying modify state on         // unmounted component, throw error         cleartimeout(this.turnoffredtimeout);     }     render () {         // ui show how *could* work         return (             <div onclick={this.turnlightred}>                 light {this.state.activatelightcolorforred ? "red" : "green"}.                 <br /> click change!             </div>         )     } }

hope helps.


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