EmitLightTag

Emit Light Tag

Searching a heavily modded pack for every block that gives off light usually means scrolling through JEI/EMI by hand and hoping you didn't miss anything. This mod builds the list for you.

At runtime, it scans every block currently loaded, vanilla or modded, and checks whether any of its possible states can emit light, not just its default appearance. That catches conditional sources too: an unlit redstone lamp still counts, since it lights up once powered, and the same goes for candles, sea pickles, and anything else that only glows under specific conditions. The result gets written into a real c:emits_light tag, mirrored onto the matching items, so typing #emits_light into JEI or EMI's search bar returns the full list.

A plain datapack can't do this. Block light emission is defined in each mod's Java code, not in JSON, so a static file can never account for whatever mod list a player actually has installed. Generating the tag at runtime is the only way to keep it accurate.

No JEI or EMI plugin code is required. Both already support #tag search on their own, so the mod works the same whether you have one, both, or neither installed. If another mod or datapack already defines entries for c:emits_light, this merges with them instead of overwriting.

Available for Fabric 1.20.1 and NeoForge 1.21.1.

This only affects search. It doesn't touch recipes, loot tables, or crafting.