🔰statement vs. declaration

🚧 施工中

JS ⟩ grammar ⟩ statement vs. declaration

statements and declarations are two disjoint sets of grammars.

• the following are (9) declarations:

  • let, const

  • function, function*

  • async function, async function*

  • class

  • export, import (can only appear at the top-level of a module)

• everything else in this list is a statement.

⭐️ 重點

statement vs. declaration

• var is a statement❗

• let/const is a declaration.

👉 statement expected❗️❗

• declaration： binding identifier to value.

• statement： carrying out actions.

📘 手冊