JSFiddle - React, Tailwind, and code Playground

by Steven Senkus

JavaScript

function removeDuplicates(str) {
    let resultString = '';

    function isDuplicateCaseInsensitiveChar(result, char) {
        return (result.indexOf(char.toUpperCase()) !== -1 || result.indexOf(char.toLowerCase()) !== -1);
    }

	if (typeof str !== 'string') {
    	console.log('Input was not a string!');
    	return;
    }

    for (let i = 0; i < str.length; i++) {
        if (!isDuplicateCaseInsensitiveChar(resultString, str[i])) {
            resultString += str[i];
        }
    }
    return resultString;
}

let input = "AbraCadABraAlakAzam";
console.log(removeDuplicates(input));