The for Tag

Repetition is a tag too. <for> iterates anything iterable via its of= attribute, handing each item to its content through tag parameters — the names between pipes:

<for|item, index| of=["a", "b", "c"]>
  ${index}: ${item}
</for>

Read |item, index| as the loop’s parameter list: each pass binds the current element (and optionally its position) for the content to use. You’ve already met this shape once — <await|user|=...> in a doc example — and part four generalizes it, because parameters are how any tag can hand values to its content. For now: pipes mean “the tag gives me these.”

The reading list on the right renders one hardcoded book three times. Make it real:

1. Replace the three <li> copies with a single <for|book, i| of=books> around one <li>.
2. Inside, interpolate: ${i + 1}. ${book.title} — ${book.author}.
3. Add a fourth book to the array and watch the list simply be longer.

The parameters are scoped to the content — each iteration gets its own book and i, which becomes very important two lessons from now.