This gist was created to share the code for the phaser.io "Making your first Phaser 3 game", with a few adjustments of mine, with one of my students.

phaser-demo-project-edit-game.js

const ZERO = 0;
const GAME_WIDTH = 800;
const GAME_HEIGHT = 600;
const TWO = 2;

var platforms;
var player;
var cursors;
var stars;
var bombs;

var score = 0;
var scoreText;

var config = {
  type: Phaser.AUTO,
  width: GAME_WIDTH,
  height: GAME_HEIGHT,
  physics: {
    default: 'arcade',
    arcade: {
        gravity: { y: 300 },
        debug: false
    }
  },
  scene: {
      preload: preload,
      create: create,
      update: update
  }
};

var game = new Phaser.Game(config);

function preload() {
  this.load.image('sky', 'assets/sky.png');
  this.load.image('ground', 'assets/platform.png');
  this.load.image('star', 'assets/star.png');
  this.load.image('bomb', 'assets/bomb.png');
  this.load.spritesheet(
    'dude',
    'assets/dude.png',
    {
      frameWidth: 32,
      frameHeight: 48
    }
  );
}

function create() {
  this.add.image(GAME_WIDTH/TWO, GAME_HEIGHT/TWO, 'sky');

  platforms = this.physics.add.staticGroup();

  platforms.create(400, 568, 'ground').setScale(2).refreshBody();

  platforms.create(600, 400, 'ground');
  platforms.create(50, 250, 'ground');
  platforms.create(750, 220, 'ground');

  player = this.physics.add.sprite(100, 450, 'dude');

  player.setBounce(0.2);
  player.setCollideWorldBounds(true);

  this.anims.create({
    key: 'left',
    frames: this.anims.generateFrameNumbers(
      'dude',
      {
        start: 0,
        end: 3
      }
    ),
    frameRate: 10,
    repeat: -1
  });

  this.anims.create({
    key: 'turn',
    frames: [{
      key: 'dude',
      frame: 4
    }],
    frameRate: 20
  });

  this.anims.create({
    key: 'right',
    frames: this.anims.generateFrameNumbers(
      'dude',
      {
        start: 5,
        end: 8
      }
    ),
    frameRate: 10,
    repeat: -1
  });

  this.physics.add.collider(player, platforms);

  cursors = this.input.keyboard.createCursorKeys();

  stars = this.physics.add.group({
    key: 'star',
    repeat: 11,
    setXY: {
      x: 15,
      y: 0,
      stepX: 70
    }
  });

  stars.children.iterate(function(child) {
    child.setBounce(Phaser.Math.FloatBetween(0.4, 0.8));
  });

  this.physics.add.collider(stars, platforms);

  this.physics.add.overlap(player, stars, collectStar, null, this);

  scoreText = this.add.text(
    16,
    16,
    'score: 0',
    {
      fontSize: '32px',
      fill: '#000'
    }
  );

  bombs = this.physics.add.group();

  this.physics.add.collider(bombs, platforms);
  this.physics.add.collider(player, bombs, hitBomb, null, this);
}

function update() {
  if (cursors.left.isDown)
  {
    player.setVelocityX(-160);
    player.anims.play('left', true);
  }
  else if (cursors.right.isDown) {
    player.setVelocityX(160);
    player.anims.play('right', true);
  }
  else {
    player.setVelocityX(0);
    player.anims.play('turn');
  }

  if(cursors.up.isDown && player.body.touching.down) {
    player.setVelocityY(-330);
  }
}

// other functions
function collectStar(player, star)
{
  star.disableBody(true, true);

  score += 10;
  scoreText.setText('Score: ' + score);

  // add bombs
  if(stars.countActive(true) === 0 ) {
    stars.children.iterate(function(child) {
      child.enableBody(true, child.x, 0, true, true);
    });

    var bombPosX = (player.x < GAME_WIDTH/TWO) ? Phaser.Math.Between(GAME_WIDTH/TWO, GAME_WIDTH) : Phaser.Math.Between(ZERO, GAME_WIDTH/TWO);

    var bomb = bombs.create(bombPosX, 16, 'bomb');
    bomb.setBounce(1);
    bomb.setCollideWorldBounds(true);
    bomb.setVelocity(Phaser.Math.Between(-200, 200), 20);
  }
}

function hitBomb(player, bomb) {
  // fix this to set player tint, make player face screen
  this.physics.pause();

  player.setTint(0xff0000);
  player.anims.play(turn);

  gameOver = true;
}