MSDN references JavaScript's Set collection abstraction. I've got an array of objects that I'd like to convert to a set so that I am able to remove (.delete()) various elements by name:
var array = [
{name: "malcom", dogType: "four-legged"},
{name: "peabody", dogType: "three-legged"},
{name: "pablo", dogType: "two-legged"}
];
How do I convert this array to a set? More specifically, is it possible to do this without iterating over the above array? The documentation is relatively lacking (sufficient for instantiated sets; not for conversions - if possible).
I may also be thinking of the conversion to a Map, for removal by key. What I am trying to accomplish is an iterable collection that can be accessed or modified via accessing the elements primarily via a key (as opposed to index).
Conversion from an array to the other being the ultimate goal.
Just pass the array to the Set constructor. The Set constructor accepts an iterable parameter. The Array object implements the iterable protocol, so its a valid parameter.
var arr = [55, 44, 65];
var set = new Set(arr);
console.log(set.size === arr.length);
console.log(set.has(65));If you start out with:
let array = [
{name: "malcom", dogType: "four-legged"},
{name: "peabody", dogType: "three-legged"},
{name: "pablo", dogType: "two-legged"}
];
And you want a set of, say, names, you would do:
let namesSet = new Set(array.map(item => item.name));
By definition "A Set is a collection of values, where each value may occur only once." So, if your array has repeated values then only one value among the repeated values will be added to your Set.
var arr = [1, 2, 3];
var set = new Set(arr);
console.log(set); // {1,2,3}
var arr = [1, 2, 1];
var set = new Set(arr);
console.log(set); // {1,2}
So, do not convert to set if you have repeated values in your array.