Converting a number from hexadecimal

Instead of using the lengthy parseInt to convert a number from hexadecimal:

parseInt(a,16) 

Add "0x" to the beginning, then convert to a number with a usual technique:

+("0x"+a) // 5 bytes saved 

Even better solution, abusing order of operations:

"0x"+a-0 // another byte saved 

Converting a number from hexadecimal

Instead of using the lengthy parseInt to convert a number from hexadecimal:

parseInt(a,16) 

Add "0x" to the beginning, then convert to a number with a usual technique:

+("0x"+a) // 5 bytes saved 

Even better solution, abusing order of operations:

"0x"+a-0 // another byte saved 

Note that this last one will not work in all situations, depending on the surrounding operators.

In ES6, you can also use this trick to convert from octal or binary:

"0b"+a-0 // binary "0o"+a-0 // octal