Walrus is a lightweight JavaScript templating engine that builds on Mustache‑style syntax but replaces the hash‑slash block delimiters with Ruby‑like `do … end` blocks and adds a rich set of built‑in helpers, filters, and view‑method support (e.g., conditionals, iteration, date/number/string utilities). It’s aimed at front‑end developers who want a small, dependency‑free library for expressive client‑side rendering with reusable view helpers.