Check for misspelled JavaScript keywords

Is your feature request related to a problem? Please describe.

The other day in a Code Nation classroom, a student had written out a simple jQuery function, but their code wasn’t working. One of the teachers couldn’t see anything wrong, and thought maybe popcode wasn’t working. Eventually, I spotted the problem: the word function was misspelled, I think as fucntion or some reversal of two letters.

Describe the solution you'd like

A small solution would be adding a specific check for misspellings of function, perhaps in contexts where we could deduce the intended word.

A bigger scope but possibly a better solution would be a code “spellchecker,” which would be super helpful in cases like this. Simple typing/spelling errors where key words are off by one letter are super common, especially for beginners (but possible for anyone and hard to debug). Other common issues are missed capitalization or hyphenation, and I believe we should try to capture these if possible, as well.

まず、エディターの JavaScript の解析またはエラー報告のエントリーポイントを特定し、無効なキーワードがどのように通知されるかを確認します。この issue ではファイルもテストも指定されていません。サポートするスペルミスのケースを定義し、function から始めて、エディターがそれらを報告できるようにカバレッジを追加します。ただし、無関係な識別子をキーワードとして扱わないようにします。