JavaScript/予約語
この章では、変数や関数などの名前として使用できない、JavaScriptの予約語の一覧を掲載しています。
予約語の種類
[編集]ECMAScript の規格では、予約語（Reserved Words）を以下の四種類に分類しています（ES1当時）。
- Keyword
- キーワード
- FutureReservedWord
- 将来のために予約された単語
- NullLiteral
- ヌルリテラル
- null
- BooleanLiteral
- 論理型リテラル
- false と true
| 単語 | ES1 | ES2 | ES3 | ES5 | ES6/2015 | ES7/2016 | ES8/2017 |
|---|---|---|---|---|---|---|---|
| abstract | N/A | FRW | ← | N/A | ← | ← | ← |
| await | N/A | ← | ← | ← | FRW | ← | K/W |
| boolean | N/A | FRW | ← | N/A | ← | ← | ← |
| break | K/W | ← | ← | ← | ← | ← | ← |
| byte | N/A | FRW | ← | N/A | ← | ← | ← |
| case | FRW | ← | K/W | ← | ← | ← | ← |
| catch | FRW | ← | K/W | ← | ← | ← | ← |
| char | N/A | FRW | ← | N/A | ← | ← | ← |
| class | FRW | ← | ← | ← | K/W | ← | ← |
| const | FRW | ← | ← | ← | K/W | ← | ← |
| continue | K/W | ← | ← | ← | ← | ← | ← |
| debugger | FRW | ← | ← | K/W | ← | ← | ← |
| default | FRW | ← | K/W | ← | ← | ← | ← |
| delete | K/W | ← | ← | ← | ← | ← | ← |
| do | FRW | ← | K/W | ← | ← | ← | ← |
| double | N/A | FRW | ← | N/A | ← | ← | ← |
| else | K/W | ← | ← | ← | ← | ← | ← |
| enum | FRW | ← | ← | ← | ← | ← | ← |
| export | FRW | ← | ← | ← | K/W | ← | ← |
| extends | FRW | ← | ← | ← | K/W | ← | ← |
| false | Bool | ← | ← | ← | ← | ← | ← |
| final | N/A | FRW | ← | N/A | ← | ← | ← |
| finally | FRW | ← | K/W | ← | ← | ← | ← |
| for | K/W | ← | ← | ← | ← | ← | ← |
| float | N/A | FRW | ← | N/A | ← | ← | ← |
| function | K/W | ← | ← | ← | ← | ← | ← |
| goto | N/A | FRW | ← | N/A | ← | ← | ← |
| if | K/W | ← | ← | ← | ← | ← | ← |
| implements | N/A | FRW | ← | S/M | ← | ← | ← |
| import | FRW | ← | ← | ← | K/W | ← | ← |
| in | K/W | ← | ← | ← | ← | ← | ← |
| instanceof | N/A | FRW | K/W | ← | ← | ← | ← |
| int | N/A | FRW | ← | N/A | ← | ← | ← |
| interface | N/A | FRW | ← | S/M | ← | ← | ← |
| let | N/A | ← | ← | S/M | ← | ← | ← |
| long | N/A | FRW | ← | N/A | ← | ← | ← |
| native | N/A | FRW | ← | N/A | ← | ← | ← |
| new | K/W | ← | ← | ← | ← | ← | ← |
| null | Null | ← | ← | ← | ← | ← | ← |
| package | N/A | FRW | ← | S/M | ← | ← | ← |
| private | N/A | FRW | ← | S/M | ← | ← | ← |
| protected | N/A | FRW | ← | S/M | ← | ← | ← |
| public | N/A | FRW | ← | S/M | ← | ← | ← |
| return | K/W | ← | ← | ← | ← | ← | ← |
| short | N/A | FRW | ← | N/A | ← | ← | ← |
| static | N/A | FRW | ← | S/M | ← | ← | ← |
| super | FRW | ← | ← | ← | K/W | ← | ← |
| switch | FRW | ← | K/W | ← | ← | ← | ← |
| synchronized | N/A | FRW | ← | N/A | ← | ← | ← |
| this | K/W | ← | ← | ← | ← | ← | ← |
| throw | FRW | ← | K/W | ← | ← | ← | ← |
| throws | N/A | FRW | ← | N/A | ← | ← | ← |
| transient | N/A | FRW | ← | N/A | ← | ← | ← |
| true | Bool | ← | ← | ← | ← | ← | ← |
| try | FRW | ← | K/W | ← | ← | ← | ← |
| typeof | K/W | ← | ← | ← | ← | ← | ← |
| var | K/W | ← | ← | ← | ← | ← | ← |
| void | K/W | ← | ← | ← | ← | ← | ← |
| volatile | N/A | FRW | ← | N/A | ← | ← | ← |
| while | K/W | ← | ← | ← | ← | ← | ← |
| with | K/W | ← | ← | ← | ← | ← | ← |
| yield | N/A | ← | ← | S/M | K/W | ← | ← |
- N/A
- 予約語ではない
- FRW
- Future Reserved Word : 将来のために予約された単語
- K/W
- Keyword : キーワード
- S/M
- Strict mode : Strict モードでのみ将来のために予約された単語として識別子には使用できない。
- ←
- 左に同じ