Cannot read property 'startSystem' of undefined

[IsaacM]

Hi !

I have a problem when i want to import this line :

game.physics.startSystem(Phaser.Physics.ARCADE);

and i have this error : 

game.js:32 Uncaught TypeError: Cannot read property 'startSystem' of undefined

my main.js is that :

var game = new Phaser.Game( {
  type: Phaser.AUTO, // Which renderer to use
  width: 500, // Canvas width in pixels
  height: 500, // Canvas height in pixels
  parent: "game-container", // ID of the DOM element to add the canvas to
  scene: {
    preload: preload,
    create: create,
    update: update
  },
  physics: {
    default: "arcade",
    arcade: {
      gravity: {
        y: 0
      } // Top down game, so no gravity
    }
  }
});

let player;


function preload() {
  this.load.image("perso", "../assets/images/perso.png");
  this.load.image("tiles", "../assets/tilesets/atlas.png");
  this.load.tilemapTiledJSON("map", "../assets/tilemaps/map.json");
}

function create() {
  
  game.physics.startSystem(Phaser.Physics.ARCADE);
  
  const map = this.make.tilemap({
    key: "map"
  });

  // Parameters are the name you gave the tileset in Tiled and then the key of the tileset image in
  // Phaser's cache (i.e. the name you used in preload)
  const tileset = map.addTilesetImage("atlas", "tiles");

  // Parameters: layer name (or index) from Tiled, tileset, x, y
  const fond = map.createStaticLayer("fond", tileset, 0, 0);
  const worldLayer = map.createStaticLayer("element", tileset, 0, 0);

  worldLayer.setCollisionBetween(12, 44);
  worldLayer.setCollisionByProperty({
    collides: true
  });
  
  const debugGraphics = this.add.graphics().setAlpha(0.75);
  const spawnPoint = map.findObject("Objects", obj => obj.name === "spawnPoint");
  player = this.physics.add.sprite(spawnPoint.x, spawnPoint.y, "perso");

  const spawnPointM = map.findObject("ObjectsPosM", obj => obj.name === "spawnPointM");
  monster = this.physics.add.sprite(spawnPointM.x, spawnPointM.y, "perso");

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

  this.cameras.main.startFollow(player, true, 0.08, 0.08);
  this.cameras.main.setZoom(1.5);

  
}

function update(time, delta) {

  var speed = 300
  // Stop any previous movement from the last frame
  player.body.setVelocity(0);
  cursors = this.input.keyboard.createCursorKeys()

  // Horizontal movement
  if (cursors.left.isDown) {
    player.body.setVelocityX(-100);
  } else if (cursors.right.isDown) {
    player.body.setVelocityX(100);
  }

  // Vertical movement
  if (cursors.up.isDown) {
    player.body.setVelocityY(-100);
  } else if (cursors.down.isDown) {
    player.body.setVelocityY(100);
  }

  // Normalize and scale the velocity so that player can't move faster along a diagonal
  player.body.velocity.normalize().scale(speed);
  
}

Im sorry if my english is bad, im a french student...