Also it's possible to use Object.entries() for your loop case and get the benefit of destructuring as for the Map example for (let [k,v] of Object.entries(o)) { console.log(k, '=>', v) }

Also the thing with Maps, you are guaranteed order in the order of insertion. you wont get that with objects.

To stringify a Map jou can create an Object from the Map's entries (it might only work with stringy keys) console.log(JSON.stringify(Object.fromEntries(personMap.entries())));

I love JS and ur videos

5:20 I'm currently exploring solutions to create a huge booking calendar and I've tried using dayjs objects as keys (with data held by any date as value) and it works wonders so far.

you need to give practical examples ,about using Maps , use cases . Very cool video thanks mate

@Microphunktv-jb3kj

4 ай бұрын

when you're dealing with loads of key-value data, hash maps... Maps Are Iterable , Objects are not(so easily) Maps can be merged with arrays and converted to arrays... built in .size method it has downside too tho, no native method for serialization and parsing... const shoppintCart = [ { price: 10, amount: 1 }, { price: 15, amount: 3 }, { price: 20, amount: 2 }, ] // original code shoppintCart.reduce( (accumulator, currentItem) => { return { totalItems: accumulator.totalItems + currentItem.amount, totalPrice: accumulator.totalPrice + currentItem.amount * currentItem.price, } }, { totalItems: 0, totalPrice: 0 } //initial value object ) // { totalItems: 6, totalPrice: 45 } // with map shoppintCart.reduce( (accumulator, currentItem) => { accumulator.set('totalItems', accumulator.get('totalItems') + currentItem.amount); accumulator.set('totalPrice', accumulator.get('totalPrice') + currentItem.price); return accumulator; }, new Map([['totalItems', 0], ['totalPrice', 0]]) ) // { 'totalItems' => 6, 'totalPrice' => 45 }

Explained very well but it would have been more better if you could atleast show an example of map's usecase.. although loved the explanation ❤

how do Maps work with typescript? and can be they turned into JSON?

@Microphunktv-jb3kj

4 ай бұрын

maps don't have native method for serialization and parsing U have to use Array method. const map1 = new Map([ [1, 2], [2, 3], [4, 5] ]); const arr = Array.from(map1); const serialized = JSON.stringify(arr);

You are amazing brother! Thanks for sharing for knowledge with us! I am surprised that this channel is so underrated! I am taking your rust course right now and it's one of the best and I am going to share it with my team as the only playlist they ever need to learn rust! Thanks again! Keep up the amazing work!

@hollam224

10 ай бұрын

same here wonder why this page is underrated

IMHO Maps work best for data structures with 2 or more dimensions. In the example above it would be difficult to have an indexed collection of PersonObjects because name is not suitable as a primary key.. I use Maps for in-memory databases with unique keys that link to rows in a form. Keys are generally Base36(time()) which make them unique

JSON.stringify(Object.fromEntries(yourMap))

Well I didn't see the benefits of the Map, actually I am more convinced to use regular Objects now 😅

@Microphunktv-jb3kj

4 ай бұрын

come back after you have to loop over deeply nested objects :D