Predicates

List of Predicates

Entity

Entity Predicates are a vanilla feature, and are used in Advancements. See the Minecraft Wiki for full documentation.

TIP

The Minecraft Wiki only shows documentation for the most recent version of Minecraft. If designing an addon for Backpacked on an older version of Minecraft, the wiki may not be 100% accurate. You may find this generator helpful as it will generate the JSON and also allow you to select the Minecraft version to target.

Crafted Item

Crafted Item Predicates are a custom predicate implemented by Backpacked just for crafted items.

Key	Type	Required	Default	Description
namespace	String/Array	No	—	The owner namespace of the item. Example: minecraft or backpacked. Can also be an array of namespaces ["minecraft", "backpacked", "create"].
tag	String	No	—	An optional item tag. See Minecraft Wiki for more details.
items	Array	No	—	An optional array of item id(s). Example: ["minecraft:stick"]

Examples

Match any item

"predicate": {
    // an empty object will match everything
}

Match exactly a stick item

"predicate": {
    "items": [
        "minecraft:stick"
    ]
}

Match items that come from the mod with the namespace create and must also have the item tag create:seats

"predicate": {
    "namespace": "create",
    "tag": "create:seats"
}

Block

note

This predicate is a vanilla feature.

Block Predicate is a vanilla predicate for matching blocks, blockstates, and/or NBT of the block.

Key	Type	Required	Default	Description
blocks	Array	No	—	An optional. Example: minecraft or backpacked. Can also be an array of namespaces ["minecraft", "backpacked", "create"].
properties	Object	No	—	An optional block position predicate. See Block Position Predicate for more details.
nbt	Object	No	—	An optional NBT predicate to match against the block entity data

Examples

Block Position

Key	Type	Required	Default	Description
x	Integer/Object	No	—	An optional integer or Min Max Predicate to match the x coordinate of a block. Leaving undefined means it accepts any x coordinate.
y	Integer/Object	No	—	An optional integer or Min Max Predicate to match the y coordinate of a block. Leaving undefined means it accepts any y coordinate.
z	Integer/Object	No	—	An optional integer or Min Max Predicate to match the z coordinate of a block. Leaving undefined means it accepts any z coordinate.

Examples

Match a block position exactly at the coordiantes (0, 0, 0)

{
    "x": 0,
    "y": 0,
    "z": 0
}

Match a block position at the y-level from 0 to 63 (inclusive)

{
    "y": {
        "min": 0,
        "max": 63
    }
}

Block Snapshot

Block Snapshot Predicate is a custom predicate implemented by Backpacked that is specific for testing block snapshots. A block snapshot is a capture of a block in the world and its state at the time of capture. The data that is captured is the block state, its position, the biome the block is in, the structure if any, the dimension (e.g. overworld) and the time of day (in the captured dimension).

Key	Type	Required	Default	Description
block	Object	No	—	The owner namespace of the item. Example: minecraft or backpacked. Can also be an array of namespaces ["minecraft", "backpacked", "create"].
position	Object	No	—	An optional block position predicate. See Block Position Predicate for more details.
biomes	Array	No	—	An optional array of biome id(s) to test if the block was contained within
structures	Array	No	—	An optional array of structure id(s) to test if the captured block was contained within.
dimension	String	No	—	An optional id of a dimension type (e.g. minecraft:overworld) to test against the dimension the block snapshot was captured.
time_of_day	Integer/Object	No	—	An optional integer or min/max to test the time of day the block snapshot was captured. Ranges from 0 to 24000. The time may be fixed depending on the dimension type.

Examples

Match fully grown wheat in the dawn of the morning in the overworld

{
    "block": {
        "blocks": "minecraft:wheat",
        "properties": {
            "age": 7
        }
    },
    "dimension": "minecraft:overworld",
    "time_of_day": {
        "min": 0,
        "max": 2000
    }
}

Match a decorated pot in a trial chamber

{
    "block": {
        "blocks": "minecraft:decorated_pot"
    },
    "structures": [
        "minecraft:trial_chambers"
    ]
}

Integer Min/Max

Key	Type	Required	Default	Description
min	Integer	No	—	The owner namespace of the item. Example: minecraft or backpacked. Can also be an array of namespaces ["minecraft", "backpacked", "create"].
max	Integer	No	—	An optional block position predicate. See Block Position Predicate for more details.

Examples

Match a block position exactly at the coordiantes (0, 0, 0)

{
    "x": 0,
    "y": 0,
    "z": 0
}

Match a block position at the y-level from 0 to 63 (inclusive)

{
    "y": {
        "min": 0,
        "max": 63
    }
}