JS setter 返回 ''undefined'' 并且 getter 导致 Uncaught TypeError TypeError: Cannot convert undefined or null to object

Question

I am trying to create a simple js program of "Today's menu" using setters and getters. The program is intended to return a random key and a value of the food and the price respectivly from an array of objects.

The problem is that even it the logic is somehow OK the setters return undefined when i call:

console.log(menu.priceToCheck);
console.log(menu.mealToCheck) ;

Because of this matter when i finally try to call the getter it causes the error:

TypeError TypeError: Cannot convert undefined or null to object

The expected output should be for example:

The menu today has pizza for only 13 dollars

There is something i cannot understand as a newbee with javascript. Here is my code below:

let menu = {
  
    _meals : [
        {"burger": 14},
        {"mouzakas": 12},
        {"pasta": 10},
        {"pizza": 13},
    ],

    
    set meal(mealToCheck) {
      if (typeof mealToCheck === 'string') {
        let random_index = Math.floor(Math.random() * this._meals.length);
        let new_obj = this._meals[random_index];
        return new_obj = mealToCheck;
        
      }
      else {
        return 'input error';
      }
      
    },
    
    set price(priceToCheck) {
      if (typeof priceToCheck === 'number') {
        
        return Object.values(this.new_obj) = priceToCheck;
      }
      else {
        return 'input error';
      }
     
    },
    
    get todaysSpecial() {
     if (Object.keys(this.new_obj) !== '' && Object.values(this.new_obj) !== 0) {
        return  'The menu today has ' + Object.keys(this.new_obj) + ' for only ' + Object.values(this.new_obj) + ' dollars';

      }
     else {
       return 'Meal or price was not set correctly!'
      }
   }
    
    
    
    
    
    };
    
    console.log(menu.priceToCheck);
    console.log(menu.mealToCheck) ;
    console.log(menu.todaysSpecial);

Answer 1

You are never using the setters for priceToCheck or mealToCheck and you never defined a getter for that