This datapack will allow you to use XP to easily repair any tools/armor.
In order to use this datapack first download it, extract the zip file and put it into the datapack folder of your world. Once you do that you should either restart your world or use the "/reload" command. Now can use it by placing an armor stand down on top of an anvil (not a chipped anvil or a Damaged anvil) and renaming it to "xp" with a name tag. If you do this correctly the armor stand will become invisible. To use the new XP repair functionality just throw a damaged tool or damaged armor and it will be repaired for 10 XP. If you want to remove the invisible armorstand later just walk up to the anvil use the command "/function xp:remove".