An overview of the logic inside the "paint" function.

noInternetProject-paintOutline.js

let enemyList = [];

paint(); 

function paint() {
  //This function gets called every frame
  
  if(checkGameOver()) {
    alert('Game over');
  }
  
  enemyList.forEach(growEnemy);
  if(timeForNewEnemy()) {
    enemyList.push(createNewEnemy());
  }
  
  updateScore();
  
  window.requestAnimationFrame(paint);
}

/** Utility Functions */
function checkGameOver()   { /* ... */ }

function growEnemy(enemy)  { /* ... */ }

function timeForNewEnemy() { /* ... */ }

function createNewEnemy()  { /* ... */ }

function updateScore()     { /* ... */ }