[bshimmin]

   3.3 Use readable synonyms in place of reserved words.

   // bad
   const superman = {
     class: 'alien',
   };

   // bad
   const superman = {
     klass: 'alien',
   };

What is unreadable about "klass"? Rails, for example, uses "klass" and it's never been hard for me (or, I suspect, anyone) to understand.

[cmrn]

The problem I see with "klass" is that you can't easily talk about it to another developer. e.g.:

"Make sure you set the class-with-a-k property to 'alien'."

"Make sure you set the type property to 'alien'."

[jbergens]

They probably don't mean 'class' in the programming language sense and should therefore use another name.

[adrusi]

Well maybe they are using "class" in the OOP sense, for instance if they're implementing a programming language. Even if they're not, if they use the word "class" in the specification for what they're implementing (maybe they're representing a taxonomical hierarchy in their program and have fields named "kingdom", "phylum", "class", etc), or have the word "class" in a user facing output (maybe they're making an RPG where a character object has fields "race", "class", "level").

It's confufing to use one name inside your code and different one elsewhere.