Compound Key Reader

Name: Compound Key Reader
Author: NullSu

Compound Key Reader is a library for datapacks and mods that reads keys and values from NBT compounds stored in command storage.

FabricForgeNeoForgeQuiltServer required, client optionalBSD 2-Clause LicenseOpen source1.21 – 1.21.4

What it does

The library exposes reader functions that walk through NBT compound data, so a script can read a key, a value and a sequence position in one pass. Results are written back to storage under a result key, where other functions can pick them up. Only the server needs the library: players join without installing anything, while the server must run it.

The mod is published for Fabric, Forge, NeoForge and Quilt, and as a data pack for server platforms. Files cover 1.21 – 1.21.4, with Beta2.2+mod for 1.21.4 as the latest build from 2024-12-18. The code is under the BSD 2-Clause License and is open source, with public source code and an issue tracker.

Key features

Compound key reading
Reads keys and values from NBT compounds, so a script can address data inside a compound by its key.
Result storage
Saves the output of a read into storage under a result key, where later functions can retrieve it.
Key, value and sequence format
Iterates a compound list with each entry given as key, value and sequence position, in a foreach-style loop.
String substring access
Extracts part of a stored string between two positions and saves the piece under a key of its own.

Gallery

Use In The Game · the usage of the get function

Compatibility

Latest build for each game version and loader.

No stable releases

Every published file is a beta or alpha build.

Version

1.21.4Beta2.2+modBeta2.2+modBeta2.2+modBeta2.2+mod

1.21.3Beta2.2+modBeta2.2+modBeta2.2+modBeta2.2+mod

1.21.2Beta2.2+modBeta2.2+modBeta2.2+modBeta2.2+mod

1.21.1Beta2.2+modBeta2.2+modBeta2.2+modBeta2.2+mod

1.21Beta2.2+modBeta2.2+modBeta2.2+modBeta2.2+mod

ReleaseBetaAlphaNot available

Only full game releases are shown. This mod publishes no snapshot builds.

Use cases

Datapack scripts reading nested data

Scripts that need values buried in compound lists can read them without hand-written paths for each entry.

Who it’s for: Datapack authors and mod developers who handle NBT compound lists in command storage and want a shared reader instead of custom code. Server owners who run datapacks that depend on it must install the library on the server.

Questions

Does a player need to install Compound Key Reader?

No. Only the server must run it, while players may leave it out.

Which loaders is Compound Key Reader available for?

It is published for Fabric, Forge, NeoForge and Quilt, and as a data pack for server platforms, with files for 1.21 – 1.21.4.

Should an existing user upgrade to Beta2.1 or later?

The author text advises upgrading to Beta2.1 and following the UPGRADE.1.md guide, because some functions and their format changed.

In the catalog

Compound Key Reader is one of 3,514 Library mods on ModsFinder, and one of 2,348 Library mods for Fabric. 17,979 mods support Minecraft 1.21.4.