Deobfuscation is nothing but the reversal of the "obfuscation" performed on any program to make the source code difficult to read and understand by any third-party users.
Then these literals are used to replace references.
It also simplifies arithmetic expressions and concatenated strings.
It also renames various hex identifiers to convert them into readable formats.
Code beautification also takes place while performing DeObfuscation.
Lastly, it also performs Experimental function evaluation.
Some can work very well, while others are moderately good.
Whale Code Obfuscation is necessary, but it may be a disadvantage in certain cases.
That is why we also need DeObfuscators to help us understand the JS source code when needed.