Deduplicate chars in string nLpMLCkDfrDdnLpMLCkDfrDd -> nLpMCkDfr

dedupString.js

// Maxdamntus.forEach
function dedupString(string) {
    var acc = {
        str: "",
        map: {}
    };
    Array.prototype.forEach.call(string, function(char) {
        if (!acc.map[char.toLowerCase()]) acc.str += char;
        acc.map[char.toLowerCase()] = true;
    });
    return acc.str;
}

// Maxdamantus.reduce
function dedupString(string) {
    return Array.prototype.reduce.call(string, function(acc, char) {
        return acc.indexOf(char.toLowerCase()) < 0 ? acc + char.toLowerCase() : acc;
    }, "");
}

// Ljharb.reduce
function dedupString(string) {
    return Array.prototype.reduce.call(string, function(acc, char) {
        if (!acc.map[char.toLowerCase()]) {
            acc.str += char;
        }
        acc.map[char.toLowerCase()] = true;
        return acc;
    }, {
        str: '',
        map: {}
    }).str;
}