Sets (data structure) - Beau teaches JavaScript

See how the set data structure can be implemented. Also learn about the es6 Set object.

Code:
More information:

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[leonardodiehl]

You could've just made an extended version of the ES6 Set.
The Set was implemented optimized looking to the peculiarities of the particular Data Structure.
It is much more performant when maintaining uniqueness and removing items.

Instead of your approach, we can make an ExtendedSet, using Set as the basis for our extra methods.

const union = function(otherSet) {
const _union = new Set(this)

for(const otherSetItem of otherSet) {
_union.add(otherSetItem)
}

return _union
}

const difference = function (otherSet) {
const _difference = new Set(this)

for (const otherItem of otherSet) {
_difference.delete(otherItem)
}

return _difference
}

const intersection = function (otherSet) {
const _intersection = new Set()

for (const item of this) {
if (otherSet.has(item)) {
_intersection.add(item)
}
}

return _intersection
}

const isSuperSet = function (otherSet) {
for (const otherItem of otherSet) {
if (!this.has(otherItem)) {
return false
}
}

return true
}

function bindExtensionMethods() {
this.union = union
this.difference = difference
this.intersection = intersection
this.isSuperSet = isSuperSet
}

function ExtendedSet(...args) {
const extendedSet = new Set(...args)

return extendedSet
}

const myExtendedSet = new ExtendedSet([1, 2, 3, 4, 5])

[andriykuts]

Your difference method is not full, because if you have two sets, for example: [1, 2, 3] and [1, 5], your method will return only [2, 3] but the full difference should be [2, 3, 5]. Am I right?

[buncha]

as others have pointed out it looks like the difference method is only half done. But otherwise great tutorial, thanks!

[MrRight]

Very useful tut. Thank you!
Is there a reason that you are using var instead o const?
Also, I would have used a newer fat arrow syntax:
values1.forEach( (e) => {
unionSet.add(e);
});

[Adnoctumz]

Thanks a lot for this! Not a biggy but you forgot to define index in line 25, it will fail silently in codepen if you try to switch to a ES6 Class

[quantum-t]

Why dont you use prototypes when adding functions (methods)??

[visintel]

I was expecting you would discuss some performance metrics. A big part of why sets are useful is their computational complexity

[tahasaleh]

Why do we use "var collection = []" instead of "this.collection = []"?

[yumingui]

It seems that "mySet" would have serious performance issues.