phaser/examples/groups/sub groups - group length.js

var game = new Phaser.Game(800, 600, Phaser.CANVAS, 'phaser-example', { preload: preload, create: create, render: render });

// Groups for storing friends and enemies, may use for collision later.
var friendAndFoe;
var enemies;

// Groups for teaming up stuff.
var normalBaddies;
var purpleBaddies;

function preload() {

    game.load.image('ufo', 'assets/sprites/ufo.png');
    game.load.image('baddie', 'assets/sprites/space-baddie.png');
    game.load.image('purple-baddie', 'assets/sprites/space-baddie-purple.png');
    
}

function create() {

    // Create some local groups for later use.
    friendAndFoe = game.add.group();
    enemies = game.add.group();
    normalBaddies = game.add.group();
    purpleBaddies = game.add.group();

    
    enemies.add(normalBaddies);
    enemies.add(purpleBaddies);


    // Create a ufo as a friend sprite.
    friendAndFoe.create(200, 240, 'ufo');

    // Create some enemies.
    for (var i = 0; i < 16; i++)
    {
        createBaddie();
    }

    // Tap to create new baddie sprites.
    game.input.onTap.add(createBaddie, this);

}

function createBaddie() {

    var baddie;

    // Of course, the baddies created will belong to their respective groups
    if (Math.random() > 0.5)
    {
        baddie = purpleBaddies.create(360 + Math.random() * 200, 120 + Math.random() * 200, 'purple-baddie');
    }
    else
    {
        baddie = normalBaddies.create(360 + Math.random() * 200, 120 + Math.random() * 200, 'baddie');
    }
    
}

function render() {

    game.debug.style = '#fff';
    game.debug.text('Tap screen or click to create new baddies.', 16, 24);
    game.debug.text('enemies: ' + enemies.length + ' (actually ' + enemies.length + ' groups)', 16, 48);
    game.debug.text('normal baddies: ' + normalBaddies.length, 16, 60);
    game.debug.text('purple baddies: ' + purpleBaddies.length, 16, 72);
    game.debug.text('friends: ' + friendAndFoe.length, 16, 96);

}