JavaScriptで変数、関数、メソッド、あるいはオブジェクトの識別子に使用してはいけないもの
- break
- case
- catch
- continue
- debugger
- default
- delete
- do
- else
- finally
- for
- function
- if
- in
- instanceof
- new
- return
- switch
- this
- throw
- try
- typeof
- var
- void
- while
- with
[予約語 - JavaScript MDN](https://developer.mozilla.org/ja/docs/Web/JavaScript/Reference/Reserved_Words)