To be able to use cheat codes, you first need to unlock access to the in-game console. To do that, you need to access "settings.ini" with any word processor (it is best to use the Notepad). You can find it in "Documents\Klei\DoNotStarve". Once inside, you need to add the following line, and click "Save".
ENABLECONSOLE = true
When you are done, start the game and press "'". You can find it to the left of "1". This way you will open the console and you will be able to enter the codes. To confirm the code hit "Enter".
All Schemata available
Press enter, and then click any item in your inventory. This way you will gain access to all schemata and will be able to create items without the necessity of having the necessary ingredients..
From now on, your hunger level will stop dropping.
Normal sanity level
You will get maximum sanity. Remember, however, that if the insanity symptoms already started to appear, this code cannot remove them.
Maximum fitness level
Uncover the entire map
Type: minimap = TheSim:FindFirstEntityWithTag("minimap")
After you hit Enter, access the console again and type:
This will uncover the entire map.