Is it possible to display output of /data from a command block?

Question

I'm playing 1.14 and wanted to test some villager mechanics in a creative world. To help debugging I thought it'd be a good idea to constantly print the home/workplace information of the closest villager, which is found in the Brain tag of the NBT data. So I wrote the following command:

/data get entity @e[type=minecraft:villager,limit=1,sort=nearest] Brain

And it works great:

So now I thought I could just put this in a command block and trigger it every second to have easy debugging. So I put this in a command block:

/execute as orlp at orlp run data get entity @e[type=minecraft:villager,limit=1,sort=nearest] Brain

However I don't get any output on triggering the command block. Even /gamerule commandBlockOutput true doesn't make it output anything.

How do I output the result of a data command ran in a command block to chat (or otherwise)?

Answer 1

Yes! 1.14 added NBT as a JSON component. So you can now print NBT like this:

/tellraw @s {"nbt":"Brain","entity":"@e[type=villager]"}

This even works for multiple entities (unlike /data get), which puts "," between the NBT outputs (which usually leads to the second and further tags appearing in a new line, because Minecraft only wraps lines on spaces, which aren't normally in NBT).

You can also output all NBT of an entity like this:

/tellraw @s {"nbt":"","entity":"@e[type=villager]"}

It also works for blocks:

/tellraw @s {"nbt":"","block":"12 -34 56"}

And you can combine "block" and "entity", then "entity" just gets ignored.

And as a special treat, you can even interpret that NBT as a JSON component, for example if you give a villager a formatted name like this:

/summon minecraft:villager ~ ~ ~ {CustomName:"{\"text\":\"Horst\",\"bold\":true}"}

…, then you can either output that JSON as text:

/tellraw @s {"nbt":"CustomName","entity":"@e[type=villager]"}

Output: {"bold":true,"text":"Horst"}

… or you can output it how it appears on top of its head:

/tellraw @s {"nbt":"CustomName","entity":"@e[type=villager]","interpret":true}

Output: Horst

And finally you can get really crazy and recursive:

/give @s written_book{author:"",title:"",pages:["{\"nbt\":\"CustomName\",\"entity\":\"@e[type=villager]\",\"interpret\":true}"]}
/tellraw @s {"nbt":"Inventory[0].tag.pages[0]","entity":"@s"}

Output: {"nbt":"CustomName","entity":"@e[type=villager]","interpret":true}

And interpreted:

/tellraw @s {"nbt":"Inventory[0].tag.pages[0]","entity":"@s","interpret":true}

Output: Horst

Note that this changes when you open the book, because then the JSON gets interpreted and the book page changes from {"nbt":"CustomName","entity":"@e[type=villager]","interpret":true} to Horst.