How to add aditional object property in array of objects?

Question

I'm trying to dynamically add additional property in the existing object. This is what I have:

let items = [
   {name: 'Carlsberg', category: 'Beer', price: '4.99'},
   {name: 'Smirnoff', category: 'Vodka', price: '28.99'},
   {name: 'Miller Lite', category: 'Beer', price: '7.99'}
]

These are the object properties which I wish to add:

categories:{
     beerCounter:2,
     vodkaCounter:1,
}

And what I want is to dynamically add additional properties of an object to look like this:

items = [
       {name: 'Carlsberg', category: 'Beer', price: '4.99', counter: categories.beerCounter},
       {name: 'Smirnoff', category: 'Vodka', price: '28.99', counter: categories.vodkaCounter},
       {name: 'Miller Lite', category: 'Beer', price: '7.99', counter: categories.beerCounter}
    ]

Answer 1

Using Array.forEach :

let items = [
   {name: 'Carlsberg', category: 'Beer', price: '4.99'},
   {name: 'Smirnoff', category: 'Vodka', price: '28.99'},
   {name: 'Miller Lite', category: 'Beer', price: '7.99'}
];

const categories = {
     beerCounter: 2,
     vodkaCounter: 1,
};

items.forEach(item => {
  item.counter = item.category === 'Beer' ? categories.beerCounter : categories.vodkaCounter;
})

console.table(items);

Answer 2

You could just iterate your array using forEach , setting the counter property using the lower-cased category value for each item:

 let items = [{ name: 'Carlsberg', category: 'Beer', price: '4.99' }, { name: 'Smirnoff', category: 'Vodka', price: '28.99' }, { name: 'Miller Lite', category: 'Beer', price: '7.99' } ] let categories = { beerCounter: 2, vodkaCounter: 1, } items.forEach(i => i.counter = categories[`${i.category.toLowerCase()}Counter`]) console.log(items)

Answer 3

You can do this with the Array.forEach() method.

I advise you to do this with a regex, it avoids keyboard errors if your category ever comes in all lowercase or all uppercase, or even a mixture of the two, sometimes our fingers wander from typing code haha

 let items = [ {name: 'Carlsberg', category: 'Beer', price: '4.99'}, {name: 'Smirnoff', category: 'Vodka', price: '28.99'}, {name: 'Miller Lite', category: 'Beer', price: '7.99'} ] const categories = { beerCounter: 2, vodkaCounter: 1, }; items.forEach(item => { if (/^beer/i.test(item.category)) { item.counter = categories.beerCounter; } if (/^vodka/i.test(item?.category)) { item.counter = categories.vodkaCounter; } }); console.log(items);

Good luck dude !

Answer 4

let items = [
   {name: 'Carlsberg', category: 'Beer', price: '4.99'},
   {name: 'Smirnoff', category: 'Vodka', price: '28.99'},
   {name: 'Miller Lite', category: 'Beer', price: '7.99'}
]

items.forEach((item) => {
  if(item.category === 'Beer'){
  item.categories = categories.beerCounter
}
})

Answer 5

You can use map or forEach

let items = [
   {name: 'Carlsberg', category: 'Beer', price: '4.99'},
   {name: 'Smirnoff', category: 'Vodka', price: '28.99'},
   {name: 'Miller Lite', category: 'Beer', price: '7.99'}
]

const categories = {
    beerCounter:2,
    vodkaCounter:1,
}

items.forEach(item=>{
  if(item.category === 'Beer')
    item.counter = categories.beerCounter;
  if(item.category === 'Vodka')
    item.counter = categories.vodkaCounter;
})

console.log(items);

Answer 6

You can map it like this. Basically the idea is to loop through all of the items and then use each item's category to map to a key in the categories object to grab the counter value for each item.

 let items = [ {name: 'Carlsberg', category: 'Beer', price: '4.99'}, {name: 'Smirnoff', category: 'Vodka', price: '28.99'}, {name: 'Miller Lite', category: 'Beer', price: '7.99'} ] let categories = { beerCounter:2, vodkaCounter:1, } for (let item of items) { item.couter = categories[`${item.category.toLowerCase()}Counter`] } console.log(items);