Simple pipe created by oliverjam - https://repl.it/Lfew/3

simple-pipe.js

// pipe takes an arbitrary number of functions as arguments
// It returns a new function waiting for a value to be passed in
function pipe(...fns) {
  return function(val) {
    let finalResult;
    for (fn of fns) {
      // Call each function in turn with val (the first time) or the previous result
      finalResult = fn(finalResult || val);
    }
    return finalResult;
  }
}

// This can be simplified a lot with arrow functions and reduce
const arrowPipe = (...fns) => val => fns.reduce((prev, fn) => fn(prev), val);

const capitalise = str => str[0].toUpperCase() + str.slice(1);

// appendChar takes a character to append and then
// returns a function waiting for a string to append the character to
const appendChar = char => x => x + char;
// We can preload it with an exclamation mark
const exclaim = appendChar('!');

// Preload pipe with the functions we want to be called
// This returns a new function waiting for a value
const formatString = pipe(
  capitalise,
  exclaim
);

// We can call this function as normal
formatString('hi'); // 'Hi!'

// Alternatively this could all be done in one go
pipe(
  capitalise,
  appendChar('!')
)('hi'); // Also 'Hi!'