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React

Posted by Ericka Erickson
Ericka Erickson
9,982 Points

why is setPlayers used and prevplayers

const [players, setPlayers] = React.useState([
    {
      name: "Guil",
      score:0,
      id: 1
    },
    {
      name: "Treasure",
      score:0,
      id: 2
    },
    {
      name: "Ashley",
      score:0,
      id: 3
    },
    {
      name: "James",
      score:0,
      id: 4
    }
  ]); 
  const handleScoreChange = (id,delta) => {
    setPlayers(prevPlayers => prevPlayers.map( player => {
      if (player.id === id){
        return{
          name:player.name,
          score:player.score + delta,
          id:player.id
        }
      }
    }));

  }

how is setPlayers a function?is it being passed a prop or another function as a prop?

where did they get prevPlayers?

2 Answers

Travis Alstrand
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STAFF
.a{fill-rule:evenodd;}techdegree
Travis Alstrand
Treehouse Teacher
Travis Alstrand
.a{fill-rule:evenodd;}techdegree
Travis Alstrand
Treehouse Teacher

Hi there Ericka Erickson ! :wave:

setPlayers is the function defined at the very top of the code you've added here. It is our way of updating our players state.

prevPlayers (or prevState) is a mechanism to access the state of a component before its latest update, ensuring reliable and consistent state transitions especially in scenarios where the new state depends on the old state. It's not something passed down as props or anything, it's a built-in functionality provided by React and the useState hook.

I hope this makes sense!

Ericka Erickson
Ericka Erickson
9,982 Points
Ericka Erickson
Ericka Erickson
9,982 Points

thanks that definitely helps!