function highlight(strings, ...values) {
  return strings.reduce((result, str, i) => {
    const value = values[i - 1];
    const transformed =
      typeof value === "number"
        ? `[${value * 2}]`
        : `(${String(value).toUpperCase()})`;
    return result + transformed + str;
  });
}

const product = "widget";
const qty = 4;
const price = 12.5;

const output = highlight`Order: ${product} x${qty} @ $${price}`;
console.log(output);

function* pipeline(...fns) {
  let value = yield;
  for (const fn of fns) {
    value = yield fn(value);
  }
  return value;
}

const double  = x => x * 2;
const addTen  = x => x + 10;
const square  = x => x * x;

const gen = pipeline(double, addTen, square);

gen.next();           // prime the generator
const r1 = gen.next(3);
const r2 = gen.next(r1.value);
const r3 = gen.next(r2.value);

console.log(r1.value, r2.value, r3.value);