---
title: JavaScript SDK 3.42.0
summary: null
url: >-
  https://www.fastly.com/documentation/reference/changes/2026/05/javascript-sdk-3.42.0
---

## Added

- Bail out of reusable sandbox if request fails ([#1453](https://github.com/fastly/js-compute-runtime/issues/1453)) ([b6f41b0](https://github.com/fastly/js-compute-runtime/commit/b6f41b0bcf429705f1a70530e39774f3fedd3c07))

## Fixed

- Allocation failure checks ([#1457](https://github.com/fastly/js-compute-runtime/issues/1457)) ([c882105](https://github.com/fastly/js-compute-runtime/commit/c882105b1daf2f16c54e25105a1d6bd45336cba5))
- Avoid dereferencing one-past-the-end iterator in `host_api` ([#1461](https://github.com/fastly/js-compute-runtime/issues/1461)) ([acf2b25](https://github.com/fastly/js-compute-runtime/commit/acf2b25fddda2960a5e5ed7b0e0e9802a2ce21c2))
- Be more defensive in `ip_octets_to_js_string` ([#1468](https://github.com/fastly/js-compute-runtime/issues/1468)) ([60bbec1](https://github.com/fastly/js-compute-runtime/commit/60bbec1f639a47ad3c384f4517aa628a2115507d))
- Cache body range check ([#1463](https://github.com/fastly/js-compute-runtime/issues/1463)) ([f38ce55](https://github.com/fastly/js-compute-runtime/commit/f38ce550419001c09e1337f2b98fd3a0b2fee947))
- Cache override getters for `beforeSend` and `afterSend` ([#1466](https://github.com/fastly/js-compute-runtime/issues/1466)) ([5261936](https://github.com/fastly/js-compute-runtime/commit/52619361172eaaed4493693f309d52e4c4f98386))
- Correct GC guard type in KVStore::put to prevent wasm unreachable crashes and fix some CI issues ([#1475](https://github.com/fastly/js-compute-runtime/issues/1475)) ([15f850d](https://github.com/fastly/js-compute-runtime/commit/15f850d47c2a407d5261f3b46047bb533bcca1dd))
- Ensure nul-termination of string for inet_pton ([#1462](https://github.com/fastly/js-compute-runtime/issues/1462)) ([0e3afbe](https://github.com/fastly/js-compute-runtime/commit/0e3afbe335a6cc29744d28283880addc780d3a04))
- Find invalid characters after nul bytes in KV store keys ([#1464](https://github.com/fastly/js-compute-runtime/issues/1464)) ([5f0f0f2](https://github.com/fastly/js-compute-runtime/commit/5f0f0f2100dce30fe8163846613d91deec783aba))
- Incorrect catch handler failure check ([#1458](https://github.com/fastly/js-compute-runtime/issues/1458)) ([fb3c01a](https://github.com/fastly/js-compute-runtime/commit/fb3c01acd8a1c696f231b265d78b26bc163adb1a))
- Memory leak in `get_found_response` ([#1456](https://github.com/fastly/js-compute-runtime/issues/1456)) ([17559d3](https://github.com/fastly/js-compute-runtime/commit/17559d350dad3969fc5d0352c1d74e38f617f78f))
- Memory leak on failed inspect hostcall ([#1455](https://github.com/fastly/js-compute-runtime/issues/1455)) ([9b77977](https://github.com/fastly/js-compute-runtime/commit/9b779773849b93d1d1b955aaea068d5e4ae73649))
- Protect against GC from `validate_bytes` ([#1447](https://github.com/fastly/js-compute-runtime/issues/1447)) ([be0867b](https://github.com/fastly/js-compute-runtime/commit/be0867ba1f7632dab107c3db15800db3a52a49ec))
- Shrinking realloc in KVStorePendingLookup ([#1467](https://github.com/fastly/js-compute-runtime/issues/1467)) ([5a72d13](https://github.com/fastly/js-compute-runtime/commit/5a72d13684679f79ff956004ff6f77fa257a6aa3))
- Throw error on negative `ttl` and `swr` ([#1465](https://github.com/fastly/js-compute-runtime/issues/1465)) ([7d29650](https://github.com/fastly/js-compute-runtime/commit/7d2965014d979dcb725b1e0c2dbbe5dcb4a20b78))