Pipe function, taken from twitter

pipe.js

// sync version
const pipe = (...fns) => x => fns.reduce((v, f) => f(v), x);

// example
const newFunc = pipe(fn1, fn2, fn3);
const result = newFunc(arg);


// async version
// take a series of promise producing functions and return a single promise
function asyncPipe(...promises) { 
  return function(initialVal) {
    return promises.reduce(
      (p, fn) => p.then(fn), 
       Promise.resolve(initialVal)
     );
  };
}

// example
async function inc(x) {
  return x + 1;
}

const pipeAsync = asyncPipe(inc, inc, inc);

pipeAsync(1).then(console.log); //=> 4