Question 179892 in Javascript Question posted in
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How do I pass a object function into another using Javascript arguments?

I am trying to pass in an ‘order’ function to ‘orderDelivery’ function through objects to synchronize with the order instead of hard coding it at the bottom

const restaurant = {
  name: 'Classico Italiano',
  location: 'Via Angelo Tavanti 23, Firenze, Italy',
  categories: ['Italian', 'Pizzeria', 'Vegetarian', 'Organic'],
  starterMenu: ['Focaccia', 'Bruschetta', 'Garlic Bread', 'Caprese Salad'],
  mainMenu: ['Pizza', 'Pasta', 'Risotto'],
  openingHours: {
    thu: {
      open: 12,
      close: 22,
    },
    fri: {
      open: 11,
      close: 23,
    },
    sat: {
      open: 0,
      close: 24,
    },
  },
  order: function (starterIndex, mainIndex) {
    return [this.starterMenu[starterIndex], this.mainMenu[mainIndex]];
  },
  
  orderDelivery: function({starterIndex, mainIndex, time, address}) {
    // ({starterIndex, mainIndex}) = this.order(2,1) attempt 1 - destructuring
    // this.order(2,1) attempt 2 - logging shows correct order but undefined
    console.log(`Order received! ${this.starterMenu[starterIndex]} and ${this.mainMenu[mainIndex]} will be delivered to ${address} at ${time}`);
  }
};

// const myOrder = restaurant.order(2, 1); attempt 3  

restaurant.orderDelivery({
  time: '22:30',
  address: 'Via del Sole, 21',
  // mainIndex: myOrder[0], attempt from 3
  // starterIndex: 2, hard code
});

I have tried destructuring but something tells me I would have to use the order function in the orderDelivery function that is outside the object but I am not really sure how. I tried assigning the order function outside and pass it through the orderDelivery but same undefined result.

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2

Answers


  1. 0

    You probably meant to build a class rather than regular Object – but here is how to do it without Classes:

    function genericOrder(starterIndex, mainIndex) 
{
    return [this.starterMenu[starterIndex], this.mainMenu[mainIndex]];
}

function genericDelivery(parameters) 
{
  console.log(`Order received! ${this.starterMenu[parameters.starterIndex]} and ${this.mainMenu[parameters.mainIndex]} will be delivered to ${parameters.address} at ${parameters.time}`);
}

const restaurant = {
  name: 'Classico Italiano',
  location: 'Via Angelo Tavanti 23, Firenze, Italy',
  categories: ['Italian', 'Pizzeria', 'Vegetarian', 'Organic'],
  starterMenu: ['Focaccia', 'Bruschetta', 'Garlic Bread', 'Caprese Salad'],
  mainMenu: ['Pizza', 'Pasta', 'Risotto'],
  openingHours: {
    thu: {
      open: 12,
      close: 22,
    },
    fri: {
      open: 11,
      close: 23,
    },
    sat: {
      open: 0,
      close: 24,
    },
  },
};

restaurant.order = genericOrder.bind(restaurant);
restaurant.orderDelivery = genericDelivery.bind(restaurant);

const myOrder = restaurant.order(2, 1);

restaurant.orderDelivery({
  time: '22:30',
  address: 'Via del Sole, 21',
  mainIndex: 0,
  starterIndex: 2,
});
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  2. 0

    You are getting undefined because when you call restaurant.orderDelivery() you must pass params spelled in exact way you defined them in orderDelivery function. This is how object destructuring works.

    You are basically defined a function which accepts an object with some desired properties as argument, so you have to pass this object with its properties in order to work. If a property is not supplied, the value of it is going to be undefined.

    Another point is your order, which returns an array composed by an element of starterMenu and one of mainMenu, so doing myOrder[0] in your case returns a string, not an index (which I guess is what you want)

    If you want the index of that items you should use Array.indexOf() on the right array containing the item you are looking for:

    restaurant.orderDelivery({
    time: '22:30',
    address: 'Via del Sole, 21',
    starterIndex: restaurant.starterMenu.indexOf(myOrder[0]),
    mainIndex: restaurant.mainMenu.indexOf(myOrder[1]),
});

    This kinda works but is a little bit tricky. You could move this searching logic inside orderDelivery function and instead of starterIndex and mainIndex you directly pass order() output:

      orderDelivery: function({orderedItems, time, address}) {
     const starterIndex = restaurant.starterMenu.indexOf(orderedItems[0])
     const mainIndex = restaurant.mainMenu.indexOf(orderedItems[1])

     console.log(`Order received! ${this.starterMenu[starterIndex]} and 
     ${this.mainMenu[mainIndex]} will be delivered to ${address} at 
     ${time}`);
  }

    So you can call restaurant.orderDelivery() in this way:

    const myOrder = restaurant.order(2, 1);

restaurant.orderDelivery({
   time: '22:30',
   address: 'Via del Sole, 21',
   orderedItems: myOrder
});
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