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Deferred: behavior different from ECMAScript Promise for objects with [[Call]] #3596

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akihikodaki opened this Issue Mar 31, 2017 · 6 comments

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akihikodaki commented Mar 31, 2017 •
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Description

jQuery's Deferred is expected to be a close approximation to Promise of ECMAScript 2016 Language Specification. Promise defined in ECMAScript 2016 tests onFulfilled, onRejected and then are objects with [[Call]].
However, isFunction, used in the Deferred, tests toStringTag, which is irrelevant from the definition. As the result, Deferred shows different behaviors for some objects such as GeneratorFunction.

Link to test case

https://jsbin.com/civabuxabe/1/edit?js,console
Expected [object Generator] { ... }, but results in 0.

jQuery.Deferred()
  .resolve(0)
  .then(function *() {})
  .then(console.log);

@akihikodaki akihikodaki referenced this issue Mar 31, 2017

Closed

Deferred: Use typeof instead of isFunction #3597

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Confirmed, but I would classify this as a bug in jQuery.isFunction rather than Deferreds, and consider improper detection of async functions to be an even bigger flaw. I'd love to switch to typeof, but doubt we actually can, especially in a minor release... even lodash still goes by toStringTag.
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gibson042 commented Mar 31, 2017

Confirmed, but I would classify this as a bug in jQuery.isFunction rather than Deferreds, and consider improper detection of async functions to be an even bigger flaw. I'd love to switch to typeof, but doubt we actually can, especially in a minor release... even lodash still goes by toStringTag.

@gibson042 gibson042 added Bug Core Needs review labels Mar 31, 2017

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akihikodaki Apr 1, 2017

lodash says:

Checks if value is classified as a Function object.

However, the standard requires the callbacks are functions (objects implementing [[Call]]). jQuery.isFunction and _.isFunction is inappropriate for the purpose.

akihikodaki commented Apr 1, 2017

lodash says:

Checks if value is classified as a Function object.

However, the standard requires the callbacks are functions (objects implementing [[Call]]). jQuery.isFunction and _.isFunction is inappropriate for the purpose.
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It can be rather difficult to perfectly determine if an object has a [[Call]] internal method, and there are some tough edge cases (none of which we properly detect now):

  • In IE9, which we still support, XML host objects have callable properties like getElementsByTagName for which typeof returns "unknown".
  • In modern browsers, document.all is callable but has typeof "undefined".

The intent of jQuery.isFunction is to serve as a reasonable approximation of ECMAScript IsCallable, and we're not going out of our way to catch every possible trick but I for one want it to recognize generators and async functions. So maybe we are at the point where typeof makes the most sense. @jquery/core would anyone else like to weigh in?
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gibson042 commented Apr 1, 2017 •
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  • @gibson042 gibson042 edited Apr 1, 2017

It can be rather difficult to perfectly determine if an object has a [[Call]] internal method, and there are some tough edge cases (none of which we properly detect now):

  • In IE9, which we still support, XML host objects have callable properties like getElementsByTagName for which typeof returns "unknown".
  • In modern browsers, document.all is callable but has typeof "undefined".

The intent of jQuery.isFunction is to serve as a reasonable approximation of ECMAScript IsCallable, and we're not going out of our way to catch every possible trick but I for one want it to recognize generators and async functions. So maybe we are at the point where typeof makes the most sense. @jquery/core would anyone else like to weigh in?
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akihikodaki Apr 1, 2017

It can be rather difficult to perfectly determine if an object has a [[Call]] internal method, and there are some tough edge cases (none of which we properly detect now):

I was not aware of these cases. By the way, I tested the second case. document.all was not callable on Firefox 52. It was callable on Chromium 57, but jQuery.isFunction(document.all) returned false. I'm still investigating those cases.

The intent of jQuery.isFunction is to serve as a reasonable approximation of ECMAScript IsCallable

A test suggests it is different from ECMAScript IsCallable.

	obj = document.createElement( "object" );

	// Firefox says this is a function
	assert.ok( !jQuery.isFunction( obj ), "Object Element" );

jquery/test/unit/core.js

Line 442 in ac9e301

obj = document.createElement( "object" );

It is callable. We may need to clarify the expected behavior of jQuery.isFunction. I have opened an issue. jquery/api.jquery.com#1034

akihikodaki commented Apr 1, 2017

It can be rather difficult to perfectly determine if an object has a [[Call]] internal method, and there are some tough edge cases (none of which we properly detect now):

I was not aware of these cases. By the way, I tested the second case. document.all was not callable on Firefox 52. It was callable on Chromium 57, but jQuery.isFunction(document.all) returned false. I'm still investigating those cases.

The intent of jQuery.isFunction is to serve as a reasonable approximation of ECMAScript IsCallable

A test suggests it is different from ECMAScript IsCallable.

	obj = document.createElement( "object" );

	// Firefox says this is a function
	assert.ok( !jQuery.isFunction( obj ), "Object Element" );

jquery/test/unit/core.js

Line 442 in ac9e301

obj = document.createElement( "object" );

It is callable. We may need to clarify the expected behavior of jQuery.isFunction. I have opened an issue. jquery/api.jquery.com#1034
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akihikodaki Apr 1, 2017

So maybe we are at the point where typeof makes the most sense. @jquery/core would anyone else like to weigh in?

Opened #3601.

akihikodaki commented Apr 1, 2017

So maybe we are at the point where typeof makes the most sense. @jquery/core would anyone else like to weigh in?

Opened #3601.
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If we pursue a fix for #3600 (which I'd like to do), then the only requirement to resolve this issue will be new unit tests.
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gibson042 commented Apr 2, 2017

If we pursue a fix for #3600 (which I'd like to do), then the only requirement to resolve this issue will be new unit tests.

@gibson042 gibson042 referenced this issue Apr 2, 2017

Closed

Core: use instanceof and typeof instead of jQuery.type in jQuery.isFunction #3601

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@gibson042 gibson042 added Deferred and removed Core Needs review labels Apr 2, 2017

This was referenced Apr 3, 2017

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@yumetodo yumetodo referenced this issue in asciidwango/js-primer Apr 4, 2017

Closed

関数宣言、関数式、Arrow Function #20

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gibson042 added a commit to gibson042/jquery that referenced this issue Apr 8, 2017

@gibson042
Core: Update isFunction to handle unusual-@@toStringTag input 
Fixes gh-3600
Fixes gh-3596
e4539b4

@gibson042 gibson042 self-assigned this Apr 8, 2017

@gibson042 gibson042 added this to the 3.3.0 milestone Apr 8, 2017

@gibson042 gibson042 referenced this issue Apr 8, 2017

Merged

Core: Update isFunction to handle unusual-@@toStringTag input #3617

4 of 4 tasks complete

@mgol mgol referenced this issue Apr 18, 2017

Closed

Can't use async functions in callbacks #3631

@gibson042 gibson042 closed this in #3617 Apr 24, 2017

gibson042 added a commit that referenced this issue Apr 24, 2017

@gibson042
Core: Update isFunction to handle unusual-@@toStringTag input 
Ref gh-3597
Fixes gh-3600
Fixes gh-3596
Closes gh-3617
a16339b

@gibson042 gibson042 referenced this issue Jan 28, 2018

Closed

use toType in isFunction, fixes #3955 #3956

2 of 4 tasks complete

restonexyz added a commit to restonexyz/jquery that referenced this issue Feb 3, 2018

@restonexyz
up (#1) 
* Dimensions: ignore transforms when retrieving width/height

Close gh-3561
Fixes gh-3193

* CSS: remove dead code in getWidthOrHeight

- getCSS already falls back to inline styles

Ref gh-3561

* Release: update release dependencies

* Release: update AUTHORS.txt

* Release: update version to 3.2.0-pre

* Release: md5sum -> md5 -r for MAC

* Build: Updating the master version to 3.2.1-pre.

* Release: edit dist README version on release

Fixes gh-3574

* Build: update PR template

- Comment out things we don't need to see in the PR description
- Change CLA link

* Tests: move readywait to an iframe test

Close gh-3576
Fixes gh-3573

* Dimensions: fall back to offsetWidth/Height for inline elems

Close gh-3577
Fixes gh-3571

* Revert "Event: Trigger checkbox and radio click events identically"

This reverts commit b442aba.

* Revert "Event: Add radio click triggering tests"

This reverts commit 5f35b5b.

* Tests: add test for passing trigger data to radio click handler

Close gh-3581
Fixes gh-3579

* Build: Updating the master version to 3.2.2-pre.

* CSS: retrieve inline style before computed

- Fixes an issue with getting computed style on detached elements

* Revert "Build: Updating the master version to 3.2.2-pre."

This reverts commit 066bd86.

* Build: Updating the master version to 3.2.2-pre.

* Tests: Fix incorrect assert name for ensure_iterability_es6

Closes gh-3584
Ref bb026fc.

* Docs: Update links to HTML spec for stripAndCollapse (#3594)

* Offset: Use correct offset parents; include all border/scroll values

Thanks @anseki

Fixes gh-3080
Fixes gh-3107
Closes gh-3096
Closes gh-3487

* Core: Update isFunction to handle unusual-@@toStringTag input

Ref gh-3597
Fixes gh-3600
Fixes gh-3596
Closes gh-3617

* Tests: Improve offset test setup and labels

Hopefully this fixes iOS testing: http://swarm.jquery.org/job/5226

Ref 1d2df77
Closes gh-3641

* Tests: Be even more async for iOS

Ref 1d2df77
Closes gh-3643

* Tests: Attach test iframes to the body for visibility-dependent code

Ref 1d2df77
Closes gh-3645

* Tests: Allow a mock QUnit.test for perfect testIframe fidelity

Ref 1d2df77
Closes gh-3647

* Tests: Prepend test iframes for even *more* consistency

Ref 1d2df77

* Tests: Reset iframe window scroll after updating html/document position

Ref 1d2df77
Closes gh-3649

* Tests: Add debugging to investigate iOS failures

Ref 1d2df77

* Tests: Keep iframes visible in TestSwarm

Ref 1d2df77

* Tests: Adjust by actual scroll position, rather than expected

Ref 1d2df77

* Tests: Clean up offset debugging

Ref 1d2df77
Ref c0edd8d

* Tests: Correct expected assertion count

Ref e94b5b0

* Tests: Revert some testIframe changes to fix dimensions tests

Ref c0edd8d

* Revert "Tests: Revert some testIframe changes to fix dimensions tests"

This reverts commit c4368a9.

* Tests: Revert some testIframe changes to fix dimensions tests

Ref c0edd8d

* CSS: Drop the float mapping from cssProps

Firefox 35 and newer support style.float directly.

Closes #3569

* Docs:Tests: Update IE/Edge-related support comments & tests

Closes gh-3661

* Build: Test on Node.js 8, stop testing on Node.js 7

* Tests: minor typos

Close gh-3671

* Dimensions: Include scroll gutter in "padding" box

Fixes gh-3589
Closes gh-3656

* Deferred: fix memory leak of promise callbacks

Fixes gh-3606
Closes gh-3657

* Build: update node dependencies; commit package-lock.json

- Also ignore yarn.lock
Close gh-3669

* Build: Update sinon, husky, and qunitjs

* Build: fix uglify options for uglify update

- Uses new typeofs option for compression
- See mishoo/UglifyJS2#2198

Close gh-3710

* Event: `stopPropagation()` on native event-handler

Fixes gh-3693
Close gh-3694

* Core: Deprecate jQuery.isWindow

Fixes gh-3629
Close gh-3702

* Test: ensure position/offset return mutable objects

Fixes gh-3612
Closes gh-3695

* Revert "Offset: Resolve strict mode ClientRect "no setter" exception"

This reverts commit 3befe59.

* Offset: fix error from bad merge in #3695

* Dimensions: Detect and account for content-box dimension mishandling

Fixes gh-3699
Closes gh-3700

* Support: Properly check for IE9 absolute scrollbox mishandling

Ref gh-3589
Fixes gh-3699
Fixes gh-3730
Closes gh-3729

* Tests: Try extra hard to control focus

Ref gh-3732

* Tests: Abort focus tests when the environment doesn't cooperate

Ref gh-3732

* Tests: Reduce the abort timeout for simple focus testing

Ref gh-3732

* Tests: Simulate events when CI hinders use of native ones

Ref gh-3732

* Tests: Account for TestSwarm focus issues

Closes gh-3732

* Ajax: add an ontimeout handler to all requests

Fixes gh-3586
Close gh-3590

* Dimensions: Improve offsetWidth/offsetHeight fallback

Fixes gh-3698
Fixes gh-3602
Closes gh-3738

* Tests: Replace non-ASCII whitespace in source code

* Dimensions: Don't trust non-pixel computed width/height

Fixes gh-3611
Closes gh-3741

* Build: Fix comment typo

Closes gh-3747

* Build: Update my name in .mailmap

I got married! 🎉

* Build: Update my name in ATHORS.txt

I forgot .mailmap isn't everything.

* Tests: Update path calculation

Fixes gh-3756
Closes gh-3757

* CSS: Avoid unit-conversion interference from CSS upper bounds

Fixes gh-2144
Closes gh-3745

* Tests: Update lineHeight adjustments to give Android more slop

* CSS: Detect more WebKit styles erroneously reported as percentages

Ref 692f9d4
Fixes gh-3777
Closes gh-3778

* Build: Update to Babel 7, use for-of plugin instead of preset-es2015

Closes gh-3786

* Build: Drop cross-spawn, use child_process.spawn shell option

* Build: increase timeout in Promises/A+ tests 10 times

The promises-aplus-tests sets up a default 200 ms Mocha timeout. This makes
our tests randomly fail on Jenkins. 2 seconds will be safer.

Closes gh-3791

* Build: Remove package-lock.json, add it to .gitignore

npm 5, even the version included in the latest Node.js 8.5.0 re-generates
`package-lock.json` on each install. And when it does on a system that doesn't
support all the optional dependencies that are supported on the OS where the
lockfile was generated, it removes those optional deps from the lockfile.

The effect is that everyone firing `npm install` on our repo on any OS other
than macOS will immediately get a dirty state of the repo as the `fsevents`
dependency subtree gets removed from `package-lock.json`. That's a really bad
experience.

This commit removes package-lock.json from the repository and adds it to
.gitignore. We'll start committing the file again once the issue is resolved
on npm's part.

Fixes gh-3792

* Tests: Make Node tests work for paths with spaces in them

Without this patch Jenkins tests fail as jQuery job names there contain spaces,
e.g. "jQuery Core".

Closes gh-3821

* Tests: Add Safari 11 support test results

* Build: Test on Node.js 9

Closes gh-3840

* Tests: Add iOS 11 support test results

* Manipulation: Reduce size by eliminating single-use variable

Closes gh-3851

* CSS: Correctly set support properties with non-default zoom

Fixes gh-3808
Closes gh-3872

* Docs: Create CODE_OF_CONDUCT.md

Close gh-3865

* Tests: Add support for running unit tests via grunt with karma

- Update QUnit to 1.23.1
- Remove unused dl#dl from test/index.html
- Remove unused map#imgmap from test/index.html
- Ensure all urls to data use baseURI
- Add the 'grunt karma:main' task
  - customContextFile & customDebugFile
- Add 'npm run jenkins' script

Close gh-3744
Fixes gh-1999

* Build: Only run browser tests in one Node version on Travis

Ref gh-3744
Closes gh-3894

* Core: make camelCase function available only for internal usage

Close gh-3604
Fixes gh-3384

* Core: adjust data tests to ensure proper camelCasing

- Add back camelCase to the public object (deprecate not remove)
Ref #3384

* Core: deprecate jQuery.now

Fixes gh-2959
Close gh-3884

* Core: deprecate jQuery.proxy (not slated for removal)

Fixes gh-2958
Close gh-3885

* Manipulation: use `.children` to select tbody elements

- selectors beginning with a child combinator are not valid natively.
  This fixes the tests when using selector-native.js

* Attributes: allow array param in add/remove/toggleClass

+30 bytes instead of +182

Thanks to @faisaliyk for the first pass on this feature.

Fixes gh-3532
Close gh-3917

* Ajax: add unit test for getScript(Object)

Fixes gh-3736
Close gh-3918

* Tests: only run ontimeout test if ontimeout exists

Fixes gh-3742
Close gh-3919

* Build: Fix UglifyJS output in Android 4.0; update uglify

- Thanks to @mgol for first pass

Fixes gh-3743
Close gh-3920

* Tests: fix function reference for unbinding

Ref gh-2958

* Build: Remove CRLF line endings to fix builds on Windows

Close gh-3929

* Core: deprecate jQuery.isFunction

Fixes gh-3609

* Event: Move event aliases to deprecated

Fixes gh-3214

* Ajax: Don't process non-string data property on no-entity-body requests

Fixes gh-3438
Closes gh-3781

* Core: deprecate jQuery.isNumeric

Fixes gh-2960
Closes gh-3888

* Tests: fix weird failure in Edge 16 CSS

Fixes gh-3866
Close gh-3932

* Tests: fix weird flaky attributes test in Edge 16

Fixes gh-3867
Close gh-3931

* Core: deprecate jQuery.type

Fixes gh-3605
Close gh-3895

* Tests: fix number of expected assertions in basic core

* Tests: temporarily require sudo access for karma:main on travis

- This should fix the broken travis build on Node 8
- See travis-ci/travis-ci#8836

* Tests: correctly set sudo in travis config, not karma config

* Manipulation: Add support for scripts with module type

Fixes gh-3871
Close gh-3869

* Tests: fix tests in AMD mode

* Tests: ensure that module assertions run on supported browsers

- Also fixes tests for karma, where the URL for the module is different

Ref gh-3871

* Filter: Use direct filter in winnow

for both simple and complex selectors

Fixes gh-3272
Closes gh-3910

* Build: Add "-debug" suffix to name of karma debug tasks

Ref gh-3922
Close gh-3936

* Tests: skip test with invalid selector for selector-native tests

* Release: add new authors to AUTHORS.txt

* Release: update version to 3.3.0-pre

* Build: Updating the master version to 3.3.1-pre.

* Build: Updating the master version to 3.3.2-pre.
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@gibson042 gibson042 referenced this issue Feb 12, 2018

Closed

wrong type check in isFunction #3955

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