a collection of Seth.js examples

seth-compare.js

/*
    This gist aims to demonstrate how sets can
    be compared in Seth.
    
    All set-to-set comparison methods begin with
    `is` such as `#isSuperset()`. And these methods
    return a Proof class instance with useful
    assertion methods.
    
    Comparisons must be proved through assertions
    as Seth is functional and the functions are
    not evaluated until called with test data.
*/

var Seth = require('seth'),
    Set = Seth.Set;

// comparison
var p1 = Seth.Everything.isSupersetOf(Seth.Numbers);
// assertion test
p1.confirms(1890); // true
p1.confirms("Kevin Spacey"); // true

// comparison
var p2 = Seth.Everything.isInverseOf(Seth.Nothing);
// assertion test
// we can really assert with any data, but..
p2.confirmsAll([1,23,4,5,6,7,8,9,10]); // true

// comparison
var p3 = Seth.Integers.isSubsetOf(Seth.Numbers);
// assertion test
p3.confirms(1890); // true
p3.confirms(Math.PI); // true

var p4 = Set([1,2,3]).isSupersetOf(Set([1,2,3,4,5]));
p4.confirmsAll([1,2,3,4,5]); // false
p4.confirmsAllExcept([1,2,3,4,5]) // [4,5]

seth-example.js

/*

	This gist aims to demonstrate the composable nature
	of Seth's functional set theory.

	Here, we define a universe of all strings called 
	`StringSet` using a simple function.

	We then create two subsets of `StringSet` called
	`SingleLineComment` and `MultiLineComment`.

	To create a set of all possible JavaScript comments, 
	a union the two sets is created, named `CommentStringSet`.

	All set-element assertions are done with 
	`Set#contains(element)`.

*/

var Seth = require('seth'),
	Set = Seth.Set;

var StringSet = Set(function(x) {
	return typeof Set === 'string';
});

// true
StringSet.contains('string');
StringSet.contains('Kevin Spacey');

// false
StringSet.contains(String);
StringSet.contains(1890);

var SingleLineComment = StringSet.subset(function(string) {
	return string.trim().slice(0,2) === '//';
});

SingleLineComment.contains('// comment'); // true
SingleLineComment.contains('/* comment */'); // false

var MultiLineComment = StringSet.subset(function(string) {
	var trimmed = string.trim(),
		head = trimmed.slice(0,2),
		tail = trimmed.slice(trimmed.length - 2);
	return head === '/*' && tail === '*/';
});

MultiLineComment.contains('// comment'); // false
MultiLineComment.contains('/* comment */'); // true

var CommentStringSet = SingleLineComment.union(MultiLineComment);

// true
CommentStringSet.contains('// comment');
CommentStringSet.contains('/* comment */');

// false
CommentStringSet.contains('string');
CommentStringSet.contains('Kevin Spacey');
CommentStringSet.contains(String);
CommentStringSet.contains(Number);

seth-literals.js

var Seth = require('seth'),
    Set = Seth.Set;
    
var A = Set([1,2,3]),
    B = Set([1,2,4]),
    C = Set([1,4]),
    D = Set([]), // or Seth.Empty
    E = Set([2,3]);

[A,B,C,D,E].filter(function(s) {
    return s.contains(2) || s.contains(4);
}).length; // 4