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JavaScript React Basics (2018) Understanding State Creating the Application State

Uche Onuekwusi
Uche Onuekwusi
17,724 Points

Since Player component renders the counter component, how come the state was created in the player component.

Since Player component renders the counter component, how come the state was created in the player component.

1 Answer

If you follow through the video, a Counter component was created that manages its own state.

...
class Counter extends React.Component {
    constructor() {
        super();
        this.state = { score : 0 }
    }

    handleIncrememtScore = () => {
        this.setState(prevState => ({ score: prevState.score + 1 }))
    }

    handleDecrememtScore = () => {
        this.setState(prevState => ({ score: prevState.score - 1 }))
    }

    render () {
        const { score } = this.state;
        return (
            <div className="counter">
                <button className="counter-action decrement" onClick={this.handleDecrememtScore}> - </button>
                <span className="counter-score"> {score} </span>
                <button className="counter-action increment" onClick={this.handleIncrememtScore}> + </button>
            </div>
        )
    }
}

const Player = ({playerName}) => {
    return (
        <div className="player">
            <span className="player-name">{playerName}</span>

            <Counter />
        </div>
    )
}

...