block specification

1.12.json

{
	"version": "1.12",
	"map_to": "1.13",
	"blocks": {
		"air": {
			"id": 0,
			"/* When state is omitted (see anvil for inclusion of state), default state of 1.13 definitions are used */": "",
			"map_to": "air"
		}, 
		"stone": {
			"id": 1,
			"maxdamage": 6,
			"map_to": {
				"variant=stone": "stone",
				"variant=granite": "granite",
				"variant=polished_granite": "polished_granite",
				"variant=diorite": "diorite",
				"variant=polished_diorite": "polished_diorite",
				"variant=andesite": "andesite",
				"variant=polished_andesite": "polished_andesite"
			},
		}, 
		"grass": {
			"id": 2, 
			"map_to": "grass_block"
		}, 
		"dirt": {
			"id": 1,
			"maxdamage": 2,
			"map_to": [
				"dirt",
				"course_dirt",
				"podzol"
			],
		},
		"anvil": {
			"id": 145,
			"maxdamage": 11,
			"map_to": [
				"anvil[facing=north]",
				"anvil[facing=east]",
				"anvil[facing=south]",
				"anvil[facing=west]",
				"chipped_anvil[facing=north]",
				"chipped_anvil[facing=east]",
				"chipped_anvil[facing=south]",
				"chipped_anvil[facing=west]",
				"damaged_anvil[facing=north]",
				"damaged_anvil[facing=east]",
				"damaged_anvil[facing=south]",
				"damaged_anvil[facing=west]",
			]
		}
	}
}

1.13.json

{
	"version": "1.13",
	"blocks": {
		"air": {
			"name": "Air", 
			"obtainable": false, 
			"stacksize": 64
		}, 
		"stone": {
			"name": "Stone",
			"obtainable": true, 
			"stacksize": 64
		},
		"granite": {
			"name": "Granite",
			"obtainable": true, 
			"stacksize": 64
		},
		"polished_granite": {
			"name": "Polished Granite",
			"obtainable": true, 
			"stacksize": 64
		},
		"diorite": {
			"name": "Diorite",
			"obtainable": true, 
			"stacksize": 64
		},
		"polished_diorite": {
			"name": "Polished Diorite",
			"obtainable": true, 
			"stacksize": 64
		},
		"andesite": {
			"name": "Andesite",
			"obtainable": true, 
			"stacksize": 64
		},
		"polished_andesite": {
			"name": "Polished Andesite",
			"obtainable": true, 
			"stacksize": 64
		},
		"grass": {
			"name": "Grass Block",
			"obtainable": true,
			"stacksize": 64
		},
		"dirt": {
			"name": "Dirt",
			"obtainable": true,
			"stacksize": 64
		},
		"coarse_dirt": {
			"name": "Coarse Dirt",
			"obtainable": true,
			"stacksize": 64
		},
		"podzol": {
			"name": "Podzol",
			"obtainable": true,
			"stacksize": 64
		},
		"anvil": {
			"name": "Anvil",
			"obtainable": true,
			"stacksize": 64,
			"/* default block state is default value for every state fully specified */": "",
			"/* default value for a state is the first item in the list */": "",
			"/* anvils would be facing=north, other blocks would have more than one state field */": "",
			"states": {
				"facing": [ "north", "east", "south", "west" ]
			}
		},
		"chipped_anvil": {
			"name": "Chipped Anvil",
			"obtainable": true,
			"stacksize": 64,
			"states": {
				"facing": [ "north", "east", "south", "west" ]
			}
		},
		"damaged_anvil": {
			"name": "Damaged Anvil",
			"obtainable": true,
			"stacksize": 64,
			"states": {
				"facing": [ "north", "east", "south", "west" ]
			}
		}
	}
}