There are truthy and falsy values in Javascript. Using them could shorten your conditional checks and more.

Falsy

• strings with the length of 0
• the number 0
• false
• undefined
• null
• NaN

Truthy

• empty arrays
• empty objects
• Everything else

Bonus

The !! operator is a useful operator to convert values in javascript to Boolean values. If the expression is a truthy value, it return true; otherwise it returns false.

!!1         // returns true
!!undefined //returns false
!![]        //returns true