Sets
ECMAScript 6 introduces sets. Sets are collections of values and can be iterated in the order of the insertion of their elements. An important characteristic about sets is that a value can occur only once in a set.
The following snippet shows some basic operations on sets:
var mySet = new Set(); mySet.add(1); mySet.add("Howdy"); mySet.add("foo"); mySet.has(1); // true mySet.delete("foo"); mySet.size; // 2 for (let item of mySet) console.log(item); // 1 // "Howdy"
We discussed briefly that JavaScript arrays are not really arrays in a traditional sense. In JavaScript, arrays are objects that have the following characteristics:
- The
length
property - The functions that inherit from
Array.prototype
(we will discuss this in the next chapter) - Special handling ...
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