1499448 - (es-fields) Implement public instance fields proposal

Status: RESOLVED FIXED

(Core :: JavaScript Engine, enhancement, P2)

Description

[Ashley Hauck [:khyperia]]

This bug is to track implementation of the public and private instance fields proposal (currently stage 3):

https://github.com/tc39/proposal-class-fields

https://tc39.github.io/proposal-class-fields/

Comment 1

[Ashley Hauck [:khyperia]]

Attachment: Bug 1499448 - Implement syntax for public and private fields.

Comment 2

[Jason Orendorff [:jorendorff]]

This new syntax should be added to jsfunfuzz. It should always trigger SyntaxErrors, for now.

Comment 4

[Gary Kwong [:gkw] [:nth10sd] (NOT official MoCo now)]

I'll endeavour to add the private identifier "#" once this lands.

Comment 5

[Jason Orendorff [:jorendorff]]

Gary, that's not all! There's also new syntax in classes to declare both public and private fields:

    class MyClass {
        field1 = "value1";  // <-- a public field
        #field2 = 12345;  // <-- a private field
        field3;  // <-- public field (initializer is optional, defaults to undefined)
        #field4 // <-- private field, no initializer, automatic semicolon insertion
    }

Comment 6

[Gary Kwong [:gkw] [:nth10sd] (NOT official MoCo now)]

Thanks! That's helpful. I suppose both public fields and private fields are only applicable wrt. classes?

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/d0b577458d53
Implement syntax for public and private fields. r=jorendorff

Comment 8

[Cristina Coroiu [:ccoroiu]]

https://hg.mozilla.org/mozilla-central/rev/d0b577458d53

Comment 9

[Cristina Coroiu [:ccoroiu]]

https://hg.mozilla.org/mozilla-central/rev/d0b577458d53

Comment 11

[Chris Mills [:cmills]]

Notes for MDN writer's team:

I've looked into our current documentation for this, and it looks like we have some mention of it here:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes#Field_declarations

However, it could do with better documentation.

I'm not sure it is worth documenting now. It doesn't seem to be supported anywhere yet (I could be wrong, but I did try testing it).

I've therefore not added a note to the Fx65 rel notes. I'd recommend waiting until it is enabled by default in Fx, or at least until Chrome enables it.

Comment 12

[Sergey Rubanov]

Public class fields will be enabled by default in next stable version of Chrome in (Jan 29)
https://v8.dev/blog/v8-release-72#public-class-fields

Comment 13

[Daniel Ehrenberg]

Neil Kakkar (https://developer.mozilla.org/en-US/profiles/neilkakkar) is currently writing the class fields documentation. If you have any suggestions for what can be improved about the current state, we'd love to hear it.

Comment 14

[Ashley Hauck [:khyperia]]

Attachment: Bug 1499448 - Implement more field functionality.

Comment 15

[Ashley Hauck [:khyperia]]

Attachment: Bug 1499448 - Implement .initializers local variable.

Comment 16

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/db4946736508
Implement more field functionality. r=jorendorff

Comment 17

[Noemi Erli[:noemi_erli]]

Backed out changeset db4946736508 (Bug 1499448) for failures in BytecodeEmitter.cpp CLOSED TREE

Push with failures: https://treeherder.mozilla.org/#/jobs?repo=autoland&resultStatus=testfailed%2Cbusted%2Cexception&classifiedState=unclassified&revision=db4946736508bb1cc3cbb288cdb498703fb4d904&selectedJob=228732500

Failure log: https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=228732409&repo=autoland&lineNumber=16674

Backout: https://hg.mozilla.org/integration/autoland/rev/8e1840b7a9923ac6e7e4c143edf87167b4cac717

Comment 18

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/49fda807b7c5
Implement more field functionality. r=jorendorff

Comment 19

[Ashley Hauck [:khyperia]]

Ah, never cleared the needinfo, whoops. Found the issue and commented in the phabricator patch.

Comment 20

[Razvan Maries]

https://hg.mozilla.org/mozilla-central/rev/49fda807b7c5

Comment 21

[Razvan Maries]

https://hg.mozilla.org/mozilla-central/rev/49fda807b7c5

Comment 22

[Jason Orendorff [:jorendorff]]

\o/

Comment 23

[Jason Orendorff [:jorendorff]]

This is becoming the meta bug for fields in JS; work should happen in bugs that block this.

Comment 24

[Ashley Hauck [:khyperia]]

Attachment: Bug 1499448 - Implement .initializers local variable.

Comment 25

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/70eb46335a2c
Implement .initializers local variable. r=jorendorff

Comment 27

[Natalia Csoregi [:nataliaCs]]

https://hg.mozilla.org/mozilla-central/rev/70eb46335a2c

Comment 28

[Cristina Coroiu [:ccoroiu]]

Backed out changeset 70eb46335a2c (bug 1499448) on request by jorendorff

Backout: https://hg.mozilla.org/integration/autoland/rev/c6197e7ad760cac9d691482130fa8ea72e7fd8de

Comment 29

[Ashley Hauck [:khyperia]]

We merged public instance fields! Woohoo!

Public static fields: bug 1535804
Private instance fields: bug 1562054

Comment 30

[Florian Scholz (Open Web Docs)]

We've updated docs for this when public fields were enabled in 69, see https://bugzilla.mozilla.org/show_bug.cgi?id=1555464#c15