astakh21 / js_is_isogram

An isogram is a word that has no repeating letters, consecutive or non-consecutive.

Write a tests for the function isIsogram that accepts a string word that contains only letters and checks whether this word is an isogram. Function returns true if word is an isogram, otherwise, return false.

Notes:

• the empty string is an isogram;
• function not case sensitive (M and m are considered the same letter).

Examples:

isIsogram('playgrounds') === true
isIsogram('look') === false
isIsogram('Adam') === false 
isIsogram('') === true

Guideline

Read more about Jest expectations