Datapack Load Events

You can load json datapack files programmatically!

onEvent('server.datapack.first',event => {
		event.addJson(name,json)
})

resourceLocation could be minecraft:loot_tables/entities/villager.json

json could be for example:

{
  type: "entity",
  pools: [
    {
      rolls: 2,
      bonus_rolls: 1,
      entries: [
        {
          type: "item",
          weight: 3,
          name: "minecraft:emerald"
        },
        {
          type: "empty",
          weight: 2
        }
      ]
    }
  ]
}

Note: Practically everything in vanilla has a way better to programmatically load it, so it is recommended to use this mostly for loading thing for other mods

There are different timing that you can make the file get loaded too!

• server.datapack.first
• server.datapack.last

This event is useful, because instead of needing to write multiple json files, you can write one then change the values passed to it.

Example

Adds multiple advancements for using different items that reward experience:

onEvent('server.datapack.first', event => {
	;['bow', 'golden_hoe', 'flint_and_steel', 'spyglass'].forEach(item => {
		event.addJson(`kubejs:advancements/${item}`, {
			criteria: {
				requirement: {
					trigger: "minecraft:using_item",
					conditions: {
						item: {
							items: [`minecraft:${item}`]
						}
					}
				}
			},
			rewards: {
				experience: 20
			}
		})
	})
})

In the custom machinery mod, the packdev needs to make a massive json file for each machine they wish to create. This script will make 16 machines, and is shorter then even a single on of the original json files would have been.

onEvent('server.datapack.first',event => {
	let json
	//create 16 custom machines with 6 inputs and 1 output
	for (let machineNumber = 0; machineNumber < 16; machineNumber++) {

		json = {
			name: {
				text: `${machineNumber}`
			},
			appearance: {},
			components: [
				{"type": "custommachinery:item",
					"id": "out",
					"mode": "output"
				}
			],
			gui: [
				{
					"type": "custommachinery:progress",
					"x": 70,
					"y": 41,
					"width": 18,
					"height": 18
				},{
					"type": "custommachinery:slot",
					"x": 88,
					"y": 41,
					"id": "out"
				},{
					"type": "custommachinery:text",
					"text": `Machine ${machineNumber}`,//string builder to make the name match the machine number
					"x":16,
					"y":16
				},{
					"type": "custommachinery:texture",
					"x": 0,
					"y": 0,
					"texture": "custommachinery:textures/gui/base_background.png",
					"priority": 1000
				},{
					"type": "custommachinery:player_inventory",
					"x": 16,
					"y": 68
				}
			]
		}

		//add the input slots and corrasponding componets
		let slotNumber = 0
		;[16,34,52].forEach(x => {
			;[32,50].forEach(y => {

				json.components.push({
					"type": "custommachinery:item",
					"id": `input${slotNumber}`,
					"mode": "input"
				})

				json.gui.push({
					"type": "custommachinery:slot",
					"x": x,
					"y": y,
					"id": `input${slotNumber}`
				})

				slotNumber++
			})
		})

		//add the json
		event.addJson(`kubejs:machines/${machineNumber}`,json)
	}
})