golden-demise

Writing functions that are nested in a functional style in JavaScript can be tricky. For instance, consider the following code:

const composeu = (unaryFunc1, unaryFunc2) => {
    return function(arg) {
        return unaryFunc2(unaryFunc1(arg));             
    };
};

In order for this to work properly, the nested function invocations need to be written inside out. Existing functions can be effectively strung together/piped in a UNIX like fashion. The spread operator (...) allows for the number of functions chained to be variable.

In the following similar example, a function calling two binary functions are called on a set of arguments (known length) is returned:

const composeb = (binFunc1, binFunc2) => {
    return function(arg1, arg2, arg3) {
        return binFunc2(binFunc1(arg1,arg2), arg3);
    }
}

You can also use these variables to control function flow, such as by storing a local variable. I wasn't able to figure out the following problem initially:

// Write a `limit` function that allows a binary function to be called a limited number of times

const limit = (binFunc, count) => {
    return function (a, b) {
        if (count >= 1) {
            count -= 1;
            return binFunc(a, b);
        }
        return undefined;
    };
}