JavaScript basics: array or arrays

Question

I'm trying to learn JavaScript and am going through an exercise where I'm creating a grocery list that populates with a food, quantity, and cost. I cannot seem to pass in multiple variables or make an array of arrays. I tried some other options like "new Object" but I can't get anything off the ground. Give me a clue?

var groceryList = function(food, quantity, price) {
  var theItem = [food, quantity, price]
  var theList = new Array();
  theList.push(theItem)

}


myList = new groceryList("cookie", 2, 1.00)
console.log(myList)

The problem is that you aren't doing anything with theList. You're just creating it, but not returning it. — Niet the Dark Absol
– Niet the Dark Absol, Commented Oct 14, 2014 at 19:58

Tom · Accepted Answer · 2014-10-14 20:00:12Z

5

Use this

var groceryList = function(food, quantity, price) {
  var theItem = [food, quantity, price]
  var theList = new Array();
  theList.push(theItem);

  return theList;
}

myList = new groceryList("cookie", 2, 1.00)
console.log(myList)

edited Oct 14, 2014 at 20:00

Tom

7,7401 gold badge26 silver badges49 bronze badges

answered Oct 14, 2014 at 19:59

Harutyun Abgaryan

2,0231 gold badge14 silver badges15 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Ryan Over a year ago

You could just return return [theItem] which would return an array instead of using the member methods of the Array object

StackSlave Over a year ago

Yeah, that would return an Array with an Array in it. Why would you want that?

Harutyun Abgaryan Over a year ago

you can try for cycle for that

Ryan · Accepted Answer · 2014-10-14 20:11:51Z

If you want to use objects, then you need to change your thinking a little bit. When you create an object with new then the constructor gets called.

function GroceryList(food, quantity, price) {
    this.food = food;
    this.quantity = quantity;
    this.price = price;
}
GroceryList.prototype.toString = function() {
  return this.food + (this.quantity).toString() + (this.price).toString();
}

// lazy array syntax
var GroceryListPool = [];


// popular the array list pool
var list1 = new GroceryList("Butter", 2, 3.999);


GroceryListPool.push(list1);

To iterate the GroceryListPool array:

for(var i = 0; i < GroceryListPool.length; i++) {
    var list = GroceryListPool[i];
    // list is an object of type GroceryList
    // technically it is not a "type", but you know what I mean.
    alert(list);
}

StackSlave · Accepted Answer · 2014-10-14 20:45:58Z

That's not even really a Constructor, yet. Check this out.

function groceryList(food, quantity, price){
  this.items = {};
  if(food !== undefined){
    this.items[food] = {quantity:quantity, price:price, total:quantity*price};
  }
  this.addItem = function(food, quantity, price){
    this.items[food] = {quantity:quantity, price:price, total:quantity*price};
  }
  this.getFood(food){
    return this.items[food];
  }
  this.getQuantity = function(food){
    return this.items[food].quantity;
  }
  this.getTotal = function(food){
    return this.items[food].total;
  }
  this.getItemsByPrice(low, high){
    var r = {}, t = this.items;
    for(var i in t){
      var f = t[i], p = f.price;
      if(p >= low && p <= high){
        r[i] = f;
      }
    }
    return r;
  }
}
var groc = new groceryList('potato', 4, 0.89);
groc.addItem('orange', 10, 1);
console.log(groc.getQuantity('potato'));
console.log(groc.getTotal('orange'));
console.log(groc.getFood('orange').price);
// same as
console.log(groc.getPrice('orange'));
// or
console.log(groc.items.orange.price);
groc.addItem('pear', 200, 0.75);
console.log(groc.getItemsByPrice(0.25, 0.99)); // should be Object with 'potato' and 'pear'

Collectives™ on Stack Overflow

JavaScript basics: array or arrays

3 Answers 3

3 Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

3 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related