// curry :: ((a, b, ...) -> c) -> a -> b -> ... -> c
function curry(fn) {
    const arity = fn.length;
    return function $curry(...args) {
        if (args.length < arity) {
            return $curry.bind(null, ...args);
        }
        return fn.call(null, ...args);
    };
}

const match = curry((what, s) => s.match(what));

const replace = curry((what, replacement, s) => s.replace(what, replacement));

const filter = curry((f, xs) => xs.filter(f));

const map = curry((f, xs) => xs.map(f));


match(/r/g, 'hello world'); // [ 'r' ]
const hasLetterR = match(/r/g); // x => x.match(/r/g)
hasLetterR('hello world'); // [ 'r' ]
hasLetterR('just j and s and t etc'); // null
filter(hasLetterR, ['rock and roll', 'smooth jazz']); // ['rock and roll']
const removeStringsWithoutRs = filter(hasLetterR); // xs => xs.filter(x => x.match(/r/g))
removeStringsWithoutRs(['rock and roll', 'smooth jazz', 'drum circle']); // ['rock androll', 'drum circle']
const noVowels = replace(/[aeiou]/ig); // (r,x) => x.replace(/[aeiou]/ig, r)
const censored = noVowels('*'); // x => x.replace(/[aeiou]/ig, '*')
censored('Chocolate Rain'); // 'Ch*c*l*t* R**n'