PartyTime is a datapack that enables you to use fireworks and fireworks explosions as VFX and SFX without damaging players, making use of subtick timing popularized by BigPapi's Delta! For Minecraft java edition 1.20.4 (also has a 1.20.2 branch). For the nerds: Details on how to mesh this pack with your own at the bottom.
This datapack has two functions for instantanous explosions, listed below:
/function n_fwk:api/burst_macro: This function will create a fireworks explosion at the location it is run. It is a macro function, where in the 'nbt' field you will pass the NBT of the entire fireworks entity as you would use in a /summon command.
Example use:
/function n_fwk:api/burst_macro {nbt:{FireworksItem:{id:"firework_rocket",Count:1,tag:{Fireworks:{Explosions:[{Type:0,Colors:[I;16755553]}]}}}}}
/function n_fwk:api/burst_storage: This function will create a fireworks explosion at the location it is run. This is not a macro function. Instead, it will look for NBT in the path api.nbt in the storage n_fwk:storage. Data stored in api.nbt is not changed by the datapack, so this is ideal for if you want to spawn multiple identical explosions.
Example use:
/data modify storage n_fwk:storage api.nbt set value {FireworksItem:{id:"firework_rocket",Count:1,tag:{Fireworks:{Explosions:[{Type:1,Colors:[I;2097121],FadeColors:[I;3828561]},{Type:2,Flicker:1b,Colors:[I;16711918],FadeColors:[I;5916528]}]}}}}
/function n_fwk:api/burst_storage
This datapack also supports making non-damaging fireworks that do not explode instantly and otherwise behave like normal fireworks. To use: either add a "n_fwk.API.no_damage" tag to the fireworks entity as it is spawned, or have the nbt tag n_fwk:{no_damage:True} stored in the items NBT data. This is only checked the first tick it exists and cannot be added later. Sorry!
Examples:
summon firework_rocket ~ ~.5 ~ {LifeTime:20,Motion:[0.0,0.1,0.0],Tags:["n_fwk.API.no_damage"],FireworksItem:{id:"firework_rocket",Count:1,tag:{Fireworks:{Explosions:[{Type:4,Colors:[I;11549695],FadeColors:[I;0]},{Type:0,Flicker:1b,Colors:[I;14484479],FadeColors:[I;0]}]}}}}
/give @p firework_rocket{n_fwk:{no_damage:True},Fireworks:{Flight:2b,Explosions:[{Type:1,Colors:[I;16774915],FadeColors:[I;16756257]}]}} 1
Notably, this part of the datapack is extremely WIP and will probably break. Feel free to report bugs but just know this is only barely supported.
All entities spawned by this datapack will have the tag "n_fwk.internal" tag. Because this uses the AEC-and-bat subtick method, make sure to add an inverted condition check for that tag to any player_hurt_entity or player_killed_entity advancements in your datapack, as they will otherwise be potentially triggered by the subtick logic of this datapack. Also, if you do anything with fireworks entities involving passengers, make sure to exclude any entities with that tag from your datapack logic.