When writing javascript, most of us default to using objects/arrays when we need to store stuff. It makes the most sense usually, but there are 2 other types that are often slept on. These types are Map and Set. Today we will be going over Map and next we will go over Set.
Map
A map is a collection of keyed data items, but unlike an object it can store the keys/values as any type, like number / boolean etc and not only strings. We can even use an object as a key, like so:
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| let john = { name: "John" };
// for every user, let's store their visits count
let visitsCountMap = new Map();
// john is the key for the map
visitsCountMap.set(john, 123);
alert(visitsCountMap.get(john)); // 123
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Nested Key Retrieval
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| // array of [key, value] pairs
let map = new Map([
['1', 'str1'],
[1, 'num1'],
[true, 'bool1']
]);
alert(map.get('1')); // str1
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Convert back to “object map”
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| let prices = Object.fromEntries([
['banana', 1],
['orange', 2],
['meat', 4]
]);
// now prices = { banana: 1, orange: 2, meat: 4 }
alert(prices.orange); // 2
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