ECS Example in Javascript / ES6

ECSExampleInES6.js

// HELPER FUNCTIONS
const has = (entity, components) => {
  const exists = (x) => typeof x !== "undefined";
  return components.map((component) => exists(entity[component]))
                   .reduce((x,y) => x && y);
};

const clone = (object) => {
  if (object === null || typeof object !== 'object'){
    return object;
  }
  
  let temp = object.constructor();
  
  for (let property in object){
    temp[property] = clone(object[property]);
  }
  
  return temp;
}; 


const compose = (f,g) =>{
  return (x) => f(g(x));
};


// ACTUAL CODE: 

const mario = {
  position : { x : 0, y : 0 },
  velocity : { x : 0, y : 0 },
  life : true,
  mass : 20,
  controllability : true,
  groundedness : true
};

const goomba = {
  position : { x : 20, y : 0 },
  velocity : { x : -1, y : 0 },
  life : true,
  mass : 10,
  groundedness : true
};

const lakituCloud = {
  position : { x : 0, y : 0},
  velocity : { x : -2, y : 0},
  life : true,
  flying : true
};

const block = {
  position : { x : 0, y : 0},
  destructability : true
};



const move = (entity) => {
  if (has(entity, ["position", "velocity"])){
    let outputEntity = clone(entity);
    outputEntity.position.x += entity.velocity.x;
    outputEntity.position.y += entity.velocity.y;
    return outputEntity;
  }else{
    return entity;
  }
};

const applyGravity = (force) => {
  return (entity) => {
    if (has(entity, ["mass", "velocity"])){
      let outputEntity = clone(entity);
      outputEntity.velocity.x += force.x / entity.mass;
      outputEntity.velocity.y += force.y / entity.mass;
      return outputEntity;
    }else{
      return entity;
    }
  };
};

const update = compose(move, applyGravity({x : 0, y : -9.81}));

const entities = [mario, goomba, lakituCloud, block];

const updatedEntities = entities.map(update);