How to write the variable s in state?

Question

How to write the variable s in state? How to write a variable in state as the key that contains snap.key from the database?

componentDidMount(){ 

    let cardQuantity = firebase.database().ref("Users"); 

    cardQuantity.on('child_added',snap => { 

        let cardsValue = cardQuantity.child(snap.key); 

        let cardId = {cardId : snap.key}; 
        this.setState({cardsId : [cardId].concat(this.state.cardsId)}); 

        let s = snap.key;
        this.setState({cards : []}); 

        cardsValue.on('value',snap => { 

            snap.forEach((childSnapshot)=> { 
                let card = {text: childSnapshot.val(), id: childSnapshot.key}; 
                //   this.setState({s : [card].concat(this.state.cards)}); 
            });
        }); 
    }) 
}

<div className="Info" > 
    { this.state.cardsId.map( cardsId => <div className="Cards" key={cardsId.cardId}> 
    //    {this.state.cards.map( card => <h2 key={card.id} >
    {card.text}</h2>) } 
</div>) }

score 2 · Accepted Answer · answered Oct 28 '17 at 21:55

2

You can do a bracket notation of the key: {[key]: value}

this.setState({[s] : [card].concat(this.state.cards)});

You can read more about this here.

answered Oct 28 '17 at 21:55

Daniel Andrei

2,654
15
16

this.state.cards == ? – Илья Литвинцев Oct 29 '17 at 04:22
Like here? {this.state.cards.map( card =>
{ card.text } < /h2>) }
– Илья Литвинцев Oct 29 '17 at 04:31
What exactly do you mean? Isn't this the question you wanted answered? – Daniel Andrei Oct 29 '17 at 08:22
How to use in the future? I need to put the written variable here - this.state.???.map() – Илья Литвинцев Oct 29 '17 at 08:45
You can do this.state[key].map() if you have the key – Daniel Andrei Oct 29 '17 at 08:48

How to write the variable s in state?

1 Answers1

{ card.text } < /h2>) }