JS — A life changing coding trick with anonymous function

Anonymous function is one of the most overlooked features in the world of JavaScript. Yet, when used correctly, it can highly improve readability and reduce line of codes. Here I would like to introduce a trick that use anonymous function for assignment, which I find extremely useful.

Image from Gift Ideas Unwrapped

The Problem

Modern coding practices suggest using const for variables that we know they won’t change. However, it becomes a bit messy when there is condition.

Say we have several conditions and we want to assign different values based on different conditions, we will end up with a long assignment chain like this:

const a = accountType === 'customer' ? ( accountStatus === 'active' ? 'active-customer-account' : 'pending-customer-account' ) : ( accountStatus === 'active' ? 'active-guest-account' : 'pending-guest-account' );

This is bad due to its unreadability. An alternative is to give up using const and use let instead:

let a;
if (accountType === 'customer') {
 if (accountStatus === 'active') {
   a = 'active-customer-account';
  } else {
   a = 'pending-customer-account';
  }
} else {
 if (accountStatus === 'active') {
   a = 'active-guest-account';
  } else {
   a = 'pending-guest-account';
  }
}