TIL - getter & setter

Minsoo·2021년 7월 23일

TIL

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5/8

☄️ Getter

Getters can perform an action on the data when getting a property.
Getters can return different values using conditionals.
In a getter, we can access the properties of the calling object using this
The functionality of our code is easier for other developers to understand.
Literally, When you get something, it will return something.
When using getter (and setter) methods is that properties cannot share the same name as the getter/setter function. Otherwise, It will cause the call stack error.
👉 그래서 게터와 세터안에 쓰여지는 변수이름을 보통 앞에'_'이용해 변수이름 다르게 함.

const person = {
  _firstName: 'John',
  _lastName: 'Doe',
  get fullName() {
    if (this._firstName && this._lastName){
      return `${this._firstName} ${this._lastName}`;
    } else {
      return 'Missing a first name or a last name.';
    }
  }
}
 // To call the getter method: 
person.fullName; // 'John Doe'

☄️ Setter

checking input, performing actions on properties, and displaying a clear intention for how the object is supposed to be used.

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 {
console.log( 'Pass in a number that is greater than or equal to 0')
}
  }
}; 
robot.numOfSensors = 100;
console.log(robot.numOfSensors)