higher-order-function-example.md

function mapConsecutive(values, fn) {
  let result = [];
  for(let i=0; i < values.length - 1; i++){
    result.push(fn(values[i], values[i+1]));
   }
   return result;
}

const letters = ['a', 'b', 'c', 'd', 'e', 'f', 'g'];
let twoByTwo = mapConsecutive(letters, (x,y) => [x,y]);
console.log(twoByTwo);
//[[a,b], [b,c], [c,d], [d,e], [e,f], [f,g]]