objectSetters.js

// Setters
// Along with getter methods, we can also create setter methods which reassign values 
// of existing properties within an object. Let’s see an example of a setter method:

const person = {
  _age: 37,
  set age(newAge){
    if (typeof newAge === 'number'){
      this._age = newAge;
    } else {
      console.log('You must assign a number to age');
    }
  }
};
// Notice that in the example above:

// We can perform a check for what value is being assigned to this._age.
// When we use the setter method, only values that are numbers will reassign this._age
// There are different outputs depending on what values are used to reassign this._age.
// Then to use the setter method:

person.age = 40;
console.log(person._age); // Logs: 40
person.age = '40'; // Logs: You must assign a number to age
// Setter methods like age do not need to be called with a set of parentheses. 
// Syntactically, it looks like we’re reassigning the value of a property.

// Like getter methods, there are similar advantages to using setter methods 
// that include checking input, performing actions on properties, and displaying
// a clear intention for how the object is supposed to be used. Nonetheless, 
// even with a setter method, it is still possible to directly reassign properties. 
// For example, in the example above, we can still set ._age directly:

person._age = 'forty-five'
console.log(person._age); // Prints forty-five

/* ----------setter method with conditions added----------- */
const robot = {
    _model: '1E78V2',
    _energyLevel: 100,
    _numOfSensors: 15,
    get numOfSensors(){
      if(typeof this._numOfSensors === 'number'){
        return this._numOfSensors;
      } else {
        return 'Sensors are currently down.'
      }
    },
    set numOfSensors(num){
      if (typeof num === 'number' && num >=0) {
        return this._numOfSensors = num;
      } else {
        return 'Pass in a number that is greater than or equal to 0';
      }
    }
  };
  
  robot.numOfSensors = 100; // setter methods do not need to be called with parens()
  console.log(robot.numOfSensors); // returns 100