Is it safe to declare a delete method in JavaScript

Question

So the question is simply, if it's safe (wise) to declare method called "delete" in JavaScript. Example:

var request = {
    delete : function (url) {
        // Some code...
    }
}
request.delete('http://page.dev/users/1');

I've tested this in Firefox and it's functional, but just wondering if it could cause problems in some other browsers; or in general if is it a good practice.

Whether it works or not, I'd avoid it just to avoid confusion. I generally stay away from any variable or member which shares a name with a language keyword. — Joe Enos, Sep 13 '13 at 19:12
possible duplicate of [javaScript reserved keywords](http://stackoverflow.com/questions/6799559/javascript-reserved-keywords) — Felix Kling, Sep 13 '13 at 19:38
and [Browser support for using a reserved word as a property name in JavaScript](http://stackoverflow.com/q/5306315/218196) — Felix Kling, Sep 13 '13 at 19:38

score 14 · Answer 1 · answered Sep 13 '13 at 19:15

According to the language specification:

Identifier Names are tokens that are interpreted according to the grammar given in the “Identifiers” section of chapter 5 of the Unicode standard, with some small modifications. An Identifier is an IdentifierName that is not a ReservedWord (see 7.6.1).

This means you cannot use delete as a variable or function name, but you can use it as an object property name. This was not the case in the previous version of the specification, which is why most other answers are recommending you avoid using reserved words entirely. However, in ES5-compliant implementations, there should be no problem.

Dave · Accepted Answer · 2013-09-13T19:17:55.027

10

You'll never have an issue if you use this['style'], but with this.style, you should avoid reserved words, which does includes delete. According to the spec, it's actually OK to use reserved words as property names, but I would avoid it anyway because there are some bad implementations around (also it just has a generally bad feel to use reserved words, whatever the context).

edited Sep 13 '13 at 19:17

answered Sep 13 '13 at 19:12

Dave

44,275
12
65
105

11

Seeing that ES-6 (23.1.3.3) will add `Map.prototype.delete` (and some other `.delete()`s), your "bad feel" should subside a bit ;) – nmaier Sep 13 '13 at 19:21
1

@nmaier in my book, it's never bad if the *standard itself* uses its own reserved words, otherwise nothing would :P But yeah I see your point. I'd still avoid it in my own code though. – Dave Sep 13 '13 at 19:27
1

You can always use `.remove()` or `.erase()` – bryc Aug 11 '15 at 15:24
1

Or you can use .destroy() – mzalazar May 19 '16 at 18:30
Or `.uninsert()` – Steven Apr 04 '23 at 06:57

score 3 · Answer 3 · answered Sep 13 '13 at 19:13

No it's not a good idea because delete is a keyword. In the newest versions, they restricted the places where it will cause problems but there still are some.

One way of avoiding any kind of problem would be to use:

var request = {
    "delete" : function (url) {
        // Some code...
    }
}
request["delete"]('http://page.dev/users/1');

But that's probably a bit less optimized and it's kind of ugly. I'd go with another name such as "remove".

score 2 · Answer 4 · answered Sep 13 '13 at 19:11

2

delete is in the JavaScript reserved words list, use at your own peril.

delete object.property

delete object['property']

answered Sep 13 '13 at 19:11

Diodeus - James MacFarlane

112,730
33
157
176

1

2 links to the same resource in 4 seconds! Not sure why yours got downvoted though. – Dave Sep 13 '13 at 19:13

score 1 · Answer 5 · answered Sep 13 '13 at 19:21

1

I'd use different keyword as other suggested - you can use synonyms like remove or purge - you get the idea.

But more important - make sure you're doing server-side validation for legibility of the call. Otherwise anybody could construct a delete call using "http://page.dev/users/1"

answered Sep 13 '13 at 19:21

Yuriy Galanter

38,833
15
69
136

Yes, I could use different name. But if I'd be able to map JS methods to HTTP methods - GET, POST, PUT, DELETE, that would look good. Anyway, I can do something like do_post, do_get, ... _I do have in mind authorization. No worries._ – VxMxPx Sep 13 '13 at 20:10
Why do you need JS method to have same names as HTTP methods? Look good for who? – Yuriy Galanter Sep 13 '13 at 20:12
1

I guess we could perceive it as some form of consistency. jQuery has methods $.post and $.get; anyway, - any better ideas are very welcome. :) – VxMxPx Sep 13 '13 at 20:19

Erik Wendel · Answer 6 · 2013-12-16T13:00:29.117

0

You should note that even using the bracket syntax for accessing properties isn't safe on all browsers.

Internet Explorer 7 and 8 will crash anyway.

edited Dec 16 '13 at 13:00

answered Dec 16 '13 at 12:54

Erik Wendel

91
2
9

Is it safe to declare a delete method in JavaScript

6 Answers6

Linked