Due to the fact the widget factory code is now in strict mode, the check for
being called without using the `new` keyword started breaking if you save the
widget constructor to a variable before calling it:
```js
var customWidget = $.custom.customWidget;
customWidget( {}, elem );
```
as then `this` is undefined and checking for `this._createWidget` crashes.
Account for that with an additional check.
Fixes gh-2015
Closes gh-2019
Fix for `options === true` when using jQuery UI under `use strict`,
which throws:
```
Uncaught TypeError: Cannot create property 'complete' on boolean 'true'
```
on line:
```js
options.complete = callback;
```
Closes gh-1931
Summary of the changes:
* Build: Add jQuery 3.2.0-3.4.1 to versions UI can be tested against
* Build: Load jQuery & Migrate via HTTPS
* Build: Add package-lock.json to .gitignore
* Build: Update jQuery Migrate from 3.0.0 to 3.1.0
* Build: Allow to run tests against jQuery 3.x-git
* Build: Fix formatting according to JSCS rules
* Build: Disable JSCS for the inlined jQuery Color
* All: Switch from $.isArray to Array.isArray (jQuery.isArray will be
removed in jQuery 4.0)
* All: Switch from `$.isFunction( x )` to `typeof x === "function"`
(jQuery.isFunction will be removed in jQuery 4.0)
* All: Inline jQuery.isWindow as it'll be removed in jQuery 4.0
* Effects: Fix a timing issue in a variable declaration. Previously,
a jQuery object was created, chained & assigned to a variable that
was then accessed in a callback used inside of this chained
definition. Due to a timing difference in when the callback fired for
the first time in latest jQuery master, it was being called before
the variable was defined.
* Tests: Make dialog & draggable unit tests less strict (newest jQuery
returns fractional results in some cases, making comparisons fail when
there's a tiny difference)
* All: Migrate from $.trim to bare String.prototype.trim (jQuery.trim
will be deprecated in jQuery 3.5)
Closes gh-1901
Affects core, effects, position and widget. Only position has unit tests
that fail with jQuery 1.6 without the workaround.
Drops the 1.6.x copies jQuery of jQuery and removes them from the select
in the testsuites.
Fixes#10723
Closes gh-1422
Disables the checks for casing and line length, since those need a lot
more effort to address. For variable naming the fix isn't obvious to me.
There's way too many lines over 100 chars.
