Deprecated and obsolete features

본 페이지는 자바스크립트의 제외 예정인(즉, 아직 사용할 수 있지만 제거 계획이 있는) 기능과 제외된(즉, 더 이상 사용할 수 없는) 기능을 나열합니다.

제외 예정 기능

아래 기능은 아직 사용할 수 있지만, 언젠가 제거될 예정이므로 주의를 기울여야 합니다. 작성한 코드가 항목 중 하나를 포함하고 있다면 제거해야 합니다.

아래 속성은 제외 예정입니다. 이는 String.replace 사용에 영향을 주지 않습니다.

Property	Description
`$1-$9`	Parenthesized substring matches, if any. Warning: Using these properties can result in problems, since browser extensions can modify them. Avoid them!
`$_`	See `input`.
`$*`	See `multiline`.
`$&`	See `lastMatch`.
`$+`	See `lastParen`.
$`	See `leftContext`.
`$'`	See `rightContext`.
`input`	The string against which a regular expression is matched.
`lastMatch`	The last matched characters.
`lastParen`	The last parenthesized substring match, if any.
`leftContext`	The substring preceding the most recent match.
`rightContext`	The substring following the most recent match.

The following are now properties of RegExp instances, no longer of the RegExp object:

Property	Description
`global`	Whether or not to test the regular expression against all possible matches in a string, or only against the first.
`ignoreCase`	Whether or not to ignore case while attempting a match in a string.
`lastIndex`	The index at which to start the next match.
`multiline`	Whether or not to search in strings across multiple lines.
`source`	패턴의 텍스트.

The caller and arguments properties are deprecated, because they leak the function caller. Instead of the arguments property, you should use the arguments object inside function closures.

getYear and setYear are affected by the Year-2000-Problem and have been subsumed by getFullYear and setFullYear.
You should use toISOString instead of the deprecated toGMTString method in new code.
toLocaleFormat is deprecated.

Proxy.create and Proxy.createFunction are deprecated. Use Proxy instead.
The following traps are obsolete:
- hasOwn (bug 980565, Firefox 33).
- getEnumerablePropertyKeys (bug 783829, Firefox 37)
- getOwnPropertyNames (bug 1007334, Firefox 33)
- keys (bug 1007334, Firefox 33)

Octal escape sequences (\ followed by one, two, or three octal digits) are deprecated in string and regular expression literals.
The escape and unescape functions are deprecated. Use encodeURI, encodeURIComponent, decodeURI or decodeURIComponent to encode and decode escape sequences for special characters.

These obsolete features have been entirely removed from JavaScript and can no longer be used as of the indicated version of JavaScript.

Property	Description
`__count__`	Returns the number of enumerable properties directly on a user-defined object.
`__parent__`	Points to an object's context.
`Object.prototype.eval()`	Evaluates a string of JavaScript code in the context of the specified object.
`Object.observe()`	Asynchronously observing the changes to an object.
`Object.unobserve()`	Remove observers.
`Object.getNotifier()`	Creates an object that allows to synthetically trigger a change.

Property	Description
`arity`	Number of formal arguments.

Property	Description
`Array.observe()`	Asynchronously observing changes to Arrays.
`Array.unobserve()`	Remove observers.

See E4X for more information.