JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/phaser-ce/2.10.2/phaser.js"></script>

JavaScript

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

var player;
var platforms;
var cursors;
var jumpButton;

function preload() {

    game.stage.backgroundColor = '#131314';

    game.load.baseURL = 'http://examples.phaser.io/assets/';
    game.load.crossOrigin = 'anonymous';

    /*game.load.image('player', 'sprites/phaser-dude.png');*/
    game.load.image('platform', 'sprites/platform.png');
    game.load.image('platform2', 'sprites/platform.png');
    
    game.load.tilemap('tilemap', 'https://hexus.github.io/phaser-arcade-slopes/assets/maps/demo.json', null, Phaser.Tilemap.TILED_JSON);
}

var player;
var platforms;
var cursors;
var jumpButton;

function create() {

    player = game.add.sprite(100, 100);

    game.physics.arcade.enable(player);

    player.body.collideWorldBounds = true;
    player.body.gravity.y = 500;

       
    
    platforms = game.add.physicsGroup();

    platforms.create(500, 150, 'platform');
    platforms.create(-200, 300, 'platform');
    platforms.create(400, 450, 'platform');

    platforms.setAll('body.immovable', true);

    cursors = game.input.keyboard.createCursorKeys();
    jumpButton = game.input.keyboard.addKey(Phaser.Keyboard.SPACEBAR);

}
function update () {

    game.physics.arcade.collide(player, platforms);

    player.body.velocity.x = 0;

    if (cursors.left.isDown)
    {
        player.body.velocity.x = -250;
    }
    else if (cursors.right.isDown)
    {
        player.body.velocity.x = 250;
    }

    if (jumpButton.isDown && (player.body.onFloor() || player.body.touching.down))
    {
        player.body.velocity.y = -400;
    }
    
     if (cursors.down.isDown) {
                 
        player.body.setSize(60, 89, 0, 0);    
        } else{
        player.body.setSize(60, 130, 0, 0); 
       
        }
}

function render () {

game.debug.body(player);
    }