mcrisc / SetJS

A Set (as in math) implementation in JavaScript

SetJS

SetJS is a pure-JavaScript implementation of the set concept aimed at efficient execution of difference (complement) and intersection operations.

Usage Examples

var res;

var a = new Set([32, 1, 5, 15, 19, 20, 20, 20, 20, 20]);
print(a);
// "Set [1, 5, 15, 19, 20, 32]"

var b = new Set([5, 15, 16, 20, 25]);
print(b);
// "Set [5, 15, 16, 20, 25]";


res = b.difference(a);
print(res);
// "Set [16, 25]";

res = b.intersection(a);
print(res);
// "Set [5, 15, 20]"

res.add(40);
print(res);
// "Set [5, 15, 20, 40]"

Supported Operations

The following common set operations are supported by SetJS:

• Membership: if (a.contains(x)) {...}
• Equality: if (a.equals(b)) {...}
• Union: res = a.union(b);
• Difference: res = b.difference(a);
• Intersection: res = b.intersection(a);

Set objects in ECMAScript 2015 (ES6)

At the time SetJS was released (2011) JavaScript (ECMAScript) lacked a set object. The latest version of ECMAScript standard (ES6) introduced set objects to JavaScript. But these are still being implemented by some browsers. Besides that, ES6 sets yet does not support some set operations.

Bellow there's a brief comparison of SetJS and ES6 set objects main features:

Operation	SetJS	ES6
iteration thru elements	no	yes
delete elements	no	yes
membership	yes	yes
equality	yes	no
difference	yes	no
intersection	yes	no