Cannot use Rust because the NodeJS `util` module is not available

I am trying to use Rust to program my screeps, and I am using wasm-bindgen for this (which is the standard way of combining Rust and JS).

However, this requires the TextDecoder API for encoding strings, which is available in the "util" module in NodeJS. But the "util" module is not available in screeps (require("util") gives an error).

In addition, TextDecoder and global.TextDecoder are not available either. Therefore I cannot use Rust with screeps.

The solution is for screeps to add in support for the "util" module in NodeJS, or alternatively upgrade to NodeJS version 11 (which has support for TextDecoder on the global object).

[josephlr]

I filed a PR upstream to get this supported: https://screeps.com/forum/topic/3067/allow-access-to-node-s-textdecoder

Interestingly, TextDecoder already works in the simulator (as the object just exists at the global scope). I was able to get a Rust “Hello World” program working in the tutorial.

[josephlr]

I don’t know anything about wasm-bindgen, but I tried your code, and yep could reproduce this. Have you a way to import a plain javascript file ? If so, you could iimport a polyfill and target in no-modules, no ?

I think the best way forward is to just give screeps add the ability to call requires("util") in their Node installation. This API has been supported since Node 8, so this should just be a config change (as screeps mandates Node 10). The current Rust API bindings for screeps use an old version of stdweb that avoids TextDecoder IIRC. The two main issues are that stdweb is no longer maintained, and the replacement wasm-bindgen (which is offically supported by the Rust project) uses the TestEncoder/Decoder APIs to speed up calling across the js/wasm boundary.

I’m not super familiar with how screeps is maintained/updated, but I’d be happy to submit a PR if someone could give me some pointers about how to change things.