`iterable-string-interceptor` is a tiny TypeScript/JavaScript utility that streams text data (e.g., from a file or any async Iterable of strings) and replaces template‑style placeholders such as `{{…}}` on the fly. By supplying a custom async transformer function, developers can inject computed values, include external files, or perform any async processing for each detected expression, making it a lightweight backbone for building custom template engines or streaming renderers.