jshint considers user delete() function as keyword, not function, yields 'function not used' for argument

[altmind]

Consider this code(you can try validate it on jshint.com)

var contactsRouter = {
  'route': function(){return this;},
  'delete': function(){return this;}
};
contactsRouter
        .route('contacts/:contact_id')
        .delete(deleteContact);

function deleteContact() {

}

JSHint yields "deleteContact" is defined, but never used.
This is wrong, deleteContact is actually used in delete().
Possibly, jshint assumes contactsRouter.delete() is keyword 'delete', not user function.
Possibly related: #1562

[caitp]

REPL says:

CONFIGURE
Metrics

There are 3 functions in this file.
Function with the largest signature take 0 arguments, while the median is 0.
Largest function has 1 statements in it, while the median is 1.
The most complex function has a cyclomatic complexity value of 1 while the median is 1.

One unused variable
9   deleteContact

[rwaldron]

Changing delete to eg. d eliminates the warning, so there is definitely a bug in how "delete" is being treated.

[jugglinmike]

The problem is a little more subtle than the bug report suggests. For example:

/* jshint unused: true */
/* jshint unused: true */
var a = {};

function before() {}

a.delete(before);
a.delete(after);

function after() {}

Results in:

One warning
9   'after' is defined but never used.

Given that there is no warning issued for the variable before above, this bug must somehow be related to hoisting. Also, this behavior extends one (but not all!) of the other keyword unary operators--typeof:

/* jshint unused: true */
var a = {};

function deleteBefore() {}
function typeofBefore() {}
function voidBefore() {}
function newBefore() {}

a.delete(deleteBefore);
a.typeof(typeofBefore);
a.void(voidBefore);
a.new(newBefore);

a.delete(deleteAfter);
a.typeof(typeofAfter);
a.void(voidAfter);
a.new(newAfter);

function deleteAfter() {}
function typeofAfter() {}
function voidAfter() {}
function newAfter() {}

issues:

Two warnings
19  'deleteAfter' is defined but never used.
20  'typeofAfter' is defined but never used.

So this is going to be a fun one.

[jugglinmike]

...I guess it's not surprising that new doesn't exhibit the bug, but you would think that void would trigger the same behavior.

[jugglinmike]

I have a solution for this, but it is dependent on gh-1903.