This mod can be downloaded here (curse forge).
This mod was made for this request: https://www.minecraftforum.net/forums/mapping-and-modding-java-edition/minecraft-mods/requests-ideas-for-mods/3030674-uncrafting-table-for-1-15
It is crafted with 8 blocks of iron and a crafting table.
You put the item you want to uncraft in the left slot and it will delete the item and output the materials it is crafted from in the right slots.
Like this, except I put another diamond pickaxe in the left slot (it will be converted to diamonds and sticks if the items are removed from the right slots.
It should be noted that only items with zero durability can be uncrafted, so partially broken tools cannot be uncrafted.
I will post the code on github in a few days.
I will add a link to the curse forge download once the project is approved.
Visual Glitch when shift clicking an item from the input slot.
Plans for future updates:
Allowing the player to choose between what they would like to uncraft the input to.
Adding a button for uncrafting the input.
Adding config options (such as making the uncrafting take experience)
Uncrafting Table (1.15.2): https://www.minecraftforum.net/forums/mapping-and-modding-java-edition/minecraft-mods/wip-mods/3032965-uncrafting-table
Ruins of Humanity (mod, no longer being developed): https://www.minecraftforum.net/forums/mapping-and-modding-java-edition/minecraft-mods/wip-mods/2898701-1-12-2-wip-early-alpha-ruins-of-humanity