Ruby 3.3 introduces range overlap? method

Rails has a built-in method called #overlaps? that allows you to compare two ranges to see if they overlap each other. This method needed to be included in Ruby.

A range is a data type that represents a sequence of values. A sequence can be any data type, including numbers, characters and dates. A range is represented using the .. and ... operators. 

// .. operator
(1..5).overlaps?(4..6)
=> true

(1..5).overlaps?(5..8)
=> true

(1..5).overlaps?(-3..0)
=> false

('a'..'z').overlaps?('c')
=> true

(Time.now..(Time.now + 5.days)).overlaps?((Time.now + 2.days)..(Time.now + 6.days))
=> true

// ... operator
(1...5).overlaps?(4...6)
=> true

(1...5).overlaps?(5...8)
=> false

(1...5).overlaps?(-1...1)
=> false

Before Ruby 3.3

To evaluate if two ranges overlap, you need to use the cover? method.

Let's say you have two ranges, a = (1..5) and b = (5..10), you can check if they overlap by using the cover? function as below:

a.eql?(b) || a.cover?(b.first) || b.cover?(a.first)
=> true

b.first returns the first value 5 of the range b. a.cover?(b.first) verifies if the value 5 is present in the range a.

The result will be false if you modify the range b to (89..120).

a.eql?(b) || a.cover?(b.first) || b.cover?(a.first)
=> false

In Ruby 3.3

With Ruby 3.3, you can use the overlap? method instead of the eql? and cover? methods.

a = (1..5)
b = (5..10)
a.overlap?(b)
=> true

a = (1..5)
b = (89..120)
a.overlap?(b)
=> false

The overlap? method works similarly for open ranges.

(1..).overlap?(...1)
=> false

(...1).overlap?(1..)
=> false

(..1).overlap?(1...)
=> true

If you pass a non-range value as a parameter to the overlap? method, it will raise TypeError.

(1..5).overlap?(1)
=> TypeError, argument must be Range

(1..5).overlap?(nil)
=> TypeError, argument must be Range

To know more about this feature, please refer to this PR.