Chapter 8, Connecting Functions – Pipelining, Composition, and More

8.1 Headline capitalization: We can make use of several functional equivalents of different methods, such as split(), map(), and join(). Using demethodize() from Chapter 6, Producing Functions, and flipTwo() from Chapter 7, Transforming Functions, would have also been possible:

const split = (str: string) => (text: string) =>
  text.split(str);
const map =
  (fn: (x: string) => string) => (arr: string[]) =>
    arr.map(fn);
const firstToUpper = (word: string): string =>
  word[0].toUpperCase() + word.substring(1).toLowerCase();
const join = (str: string) => (arr: string[]) =>
  arr.join(str);
const headline = pipeline(
  split(" "),
  map(firstToUpper),
  join(" ")
);

The pipeline works as expected: we split the string into words, we map each word to make its first letter...