Replacing Every Match With replaceAll()

Replacing Every Match With replaceAll()

In this lesson, you ported the helper’s first branch slug, which lowercases PAY-2291’s title and puts a hyphen in place of every space, since git won’t take a branch name with spaces. In Python, title.lower().replace(" ", "-") prints refund-emails-show-the-wrong-currency:-eur-shown-as-usd.

• The natural port, title.toLowerCase().replace(" ", "-"), runs without an error but prints refund-emails show the wrong currency: eur shown as usd: one hyphen, and the other eight spaces untouched.
• Given text to find, JavaScript’s replace() searches from the start, swaps the first match, and stops. Python’s replace() changes every match unless you give it a count, and title.lower().replace(" ", "-", count=1) prints the port’s line. That’s where the likeness stops: JavaScript’s replace() takes no count, and with plain text it changes one match.
• replaceAll() is the method that does what Python’s replace() does, minus the count: it always changes every match. Swap the method’s name and the port prints Python’s slug, character for character.
• Git doesn’t allow a colon in a branch name either, so the helper’s other replace removes it, and that step joins the chain before the spaces turn into hyphens. On PAY-2291’s title, replace(":", "") would give the same slug, but only because the title has one colon. Text with two, like the full header, keeps its second, so the chain uses replaceAll(":", "").
• Use replaceAll() for every match and replace() when you mean only the first. With a regular expression instead of plain text, replace() can do more, but regular expressions are a later topic.

Here’s the slug with both steps in place:

const title =
  "Refund emails show the wrong currency: EUR shown as USD";

const slug = title.toLowerCase()
  .replaceAll(":", "").replaceAll(" ", "-");
console.log(slug);