---
title: experimental
url: https://www.fastly.com/documentation/reference/compute/sdks/javascript/js-compute/experimental/
---

**Kind:** Module  
**Package:** @fastly/js-compute 4.0.1  
**Path:** `experimental`

## Interfaces

| Name | Summary |
| --- | --- |
| [ReusableSandboxOptions](https://www.fastly.com/documentation/reference/compute/sdks/javascript/js-compute/experimental/interface.ReusableSandboxOptions/) |  |

## Functions

| Name | Summary |
| --- | --- |
| [allowDynamicBackends](https://www.fastly.com/documentation/reference/compute/sdks/javascript/js-compute/experimental/fn.allowDynamicBackends/) (deprecated) | Control whether or not Dynamic Backends are allowed within this Fastly Compute service. |
| [includeBytes](https://www.fastly.com/documentation/reference/compute/sdks/javascript/js-compute/experimental/fn.includeBytes/) | Embed a file as a Uint8Array. |
| [mapAndLogError](https://www.fastly.com/documentation/reference/compute/sdks/javascript/js-compute/experimental/fn.mapAndLogError/) | Calls [mapError](https://www.fastly.com/documentation/reference/compute/sdks/javascript/js-compute/experimental/fn.mapError/) and outputs the results to stderr. |
| [mapError](https://www.fastly.com/documentation/reference/compute/sdks/javascript/js-compute/experimental/fn.mapError/) | Get information about an error as a ready-to-print array. This includes the error name, message, and a call stack. |
| [setDefaultBackend](https://www.fastly.com/documentation/reference/compute/sdks/javascript/js-compute/experimental/fn.setDefaultBackend/) (deprecated) | Set the default backend to use when dynamic backends are disabled. |
| [setReusableSandboxOptions](https://www.fastly.com/documentation/reference/compute/sdks/javascript/js-compute/experimental/fn.setReusableSandboxOptions/) | Configure reuse of the same underlying sandbox for multiple requests, which can improve performance by avoiding the overhead of initializing a new sandbox for each request. |