Isograms.js

// Kata link:
// https://www.codewars.com/kata/59dd2c38f703c4ae5e000014/train/javascript

// -------------------------------------
// Instructions:
/*
An isogram is a word that has no repeating letters, consecutive or non-consecutive. Implement a function that determines whether a string that contains only letters is an isogram. Assume the empty string is an isogram. Ignore letter case.

isIsogram("Dermatoglyphics") == true
isIsogram("aba") == false
isIsogram("moOse") == false // -- ignore letter case
*/
// -------------------------------------
// Solution 1:

// function isIsogram(str){
//     if (str.length == 0) { return true; } 
//     else {
//         let ar = Array.from(str.toLowerCase());
//         for (i of str) {
//             let n = 0;
//             for (j of ar) {
//                 if (i == j) { n += 1; }
//             }
//             if (n > 1) { return false;}
//         }
//         return true;
//     }
// }

// Solution 2:
function isIsogram(str){
    return new Set(str.toLowerCase()).size == str.length;
}

// -------------------------------------
// Basic Tests
console.log( isIsogram("Dermatoglyphics"), true );
console.log( isIsogram("isogram"), true );
console.log( isIsogram("aba"), false, "same chars may not be adjacent" );
console.log( isIsogram("moOse"), false, "same chars may not be same case" );
console.log( isIsogram("isIsogram"), false );
console.log( isIsogram(""), true, "an empty string is a valid isogram" );