Containerizing JavaScript Applications with Bazel

Containerizing JavaScript applications can be challenging due to their diverse structures, but Bazel simplifies this process with its Runfiles directory structure. Initially, the JsImageLayer rule in rules_js created two primary layers for JavaScript containers: one for infrequently changing elements like npm dependencies and Node.js interpreter, and another for application code. However, this approach proved inefficient as it required unnecessary rebuilds and redeployments when dependencies changed. To address this, version 2.0 introduced more layers to improve build and deploy times, though it wasn't a universal solution. To further optimize, the new Layer Groups feature in version 2.3.5 allows users to define additional layers based on specific criteria like file size and change frequency, enhancing performance by enabling better parallelization and reducing build times by up to 52%. This update also included utilizing libarchive for creating layers, which significantly boosted efficiency compared to previous methods.