Determine if a word or phrase is an isogram.
An isogram (also known as a "nonpattern word") is a word or phrase without a repeating letter, however spaces and hyphens are allowed to appear multiple times.
Examples of isograms:
- lumberjacks
- background
- downstream
- six-year-old
The word isograms, however, is not an isogram, because the s repeats.
Install assignment dependencies:
$ yarnExecute the tests with:
$ yarn testWikipedia https://en.wikipedia.org/wiki/Isogram