Registry Data Exchange

class SceneA extends Phaser.Scene {

    constructor ()
    {
        super('GameScene');

        this.score = 0;
        this.lives = 6;
    }

    preload ()
    {
        this.load.setBaseURL('https://cdn.phaserfiles.com/v410');
        this.load.image('bg', 'assets/skies/sky4.png');
        this.load.image('crate', 'assets/sprites/crate.png');
    }

    create ()
    {
        //  Store the score and lives in the Game Registry
        this.registry.set('score', this.score);
        this.registry.set('lives', this.lives);

        this.add.image(400, 300, 'bg');

        for (let i = 0; i < 64; i++)
        {
            let x = Phaser.Math.Between(0, 800);
            let y = Phaser.Math.Between(0, 600);

            let box = this.add.image(x, y, 'crate').setInteractive();

            if (i % 2)
            {
                box.setTint(0xff0000);
            }
        }

        this.input.on('gameobjectup', this.clickHandler, this);
    }

    clickHandler (pointer, box)
    {
        if (this.lives === 0)
        {
            return;
        }

        //  Disable our box
        box.input.enabled = false;
        box.setVisible(false);

        //  If the box was tinted red, you lose a life

        if (box.tintTopLeft === 16711680)
        {
            this.lives--;
            this.registry.set('lives', this.lives);
        }
        else
        {
            this.score++;
            this.registry.set('score', this.score);
        }
    }

}

class SceneB extends Phaser.Scene {

    constructor ()
    {
        super({ key: 'UIScene', active: true });

        this.scoreText;
        this.livesText;
    }

    create ()
    {
        //  Our Text object to display the Score
        this.scoreText = this.add.text(10, 10, 'Score: 0', { font: '32px Arial', fill: '#000000' });
        this.livesText = this.add.text(10, 48, 'Lives: 6', { font: '32px Arial', fill: '#000000' });

        //  Check the Registry and hit our callback every time the 'score' value is updated
        this.registry.events.on('changedata', this.updateData, this);
    }

    updateData (parent, key, data)
    {
        if (key === 'score')
        {
            this.scoreText.setText('Score: ' + data);
        }
        else if (key === 'lives')
        {
            this.livesText.setText('Lives: ' + data);
        }
    }
}

let config = {
    scale: { mode: Phaser.Scale.FIT },
    type: Phaser.AUTO,
    width: 800,
    height: 600,
    backgroundColor: '#000000',
    parent: 'game-container',
    scene: [ SceneA, SceneB ]
};

let game = new Phaser.Game(config);