Cassidoo code question #250

all_unique.js

function allUnique(string) {
    if (string.length !== (new Set(string)).size) {
        console.log(`Duplicate characters, same case, in '${string}'`);
        return false;
    } else {
        if (string.length !== (new Set(string.toLowerCase()).size)) {
            console.log(`Duplicate characters across cases in '${string}'`);
            return false;
        } else {
            console.log(`No duplication in '${string}'`);
            return true;
        }
    }
}
console.log(allUnique("Blue"));
console.log(allUnique("Yellow"));
console.log(allUnique("Purple"));

Problem

• Write a function that determines if all the characters in a given string are unique.
• Can you do this without making any new variables?
• You choose if you want to include capitalization in your consideration for this one, as a fun challenge.

Approach

• Avoided variable creation by testing passed parameter against manipulated versions of itself
• First, test that no characters are duplicated in the same case
• Then, test if there are no direct duplicates, can I rule out instances where capitalisation would be the only difference
• If I can rule out both of those, return true for allUnique