Arrays within JavaScript files cause the UI to hang

[helpfulBro]

Prerequisites

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Description

[Description of the issue]

Steps to Reproduce

1. Create a test.js file and save it.
2. Copy and paste a large array into the file e.g.

var occupationArray = [['Accountant','Accountant'],['Actor/Performer','Actor/Performer'],['Admin/Data Entry/Secretary','Admin/Data Entry/Secretary'],['Air Traffic Controller','Air Traffic Controller'],['Ambulance Officer/Manager','Ambulance Officer/Manager'],['Architect','Architect'],['Artist/Designer/Illustrator','Artist/Designer/Illustrator'],['Assembler','Assembler'],['Baker/Pastry Cook','Baker/Pastry Cook'],['Barrister/Solicitor','Barrister/Solicitor'],['Building/Construction Manager','Building/Construction Manager'],['Bursar','Bursar'],['Butcher/Smallgoods','Butcher/Smallgoods'],['Caretaker/Janitor','Caretaker/Janitor'],['Cashier','Cashier'],['Catering/Restaurant Manager','Catering/Restaurant Manager'],['Childcare/Youth Worker','Childcare/Youth Worker'],['Clerical Worker','Clerical Worker'],['Consultant','Consultant'],['Coroner/Judge/Magistrate','Coroner/Judge/Magistrate'],['Customer Service Consultant','Customer Service Consultant'],['Customs Agent','Customs Agent'],['Defence Forces','Defence Forces'],['Dishwasher/Kitchenhand','Dishwasher/Kitchenhand'],['Doctor/Specialist/Surgeon','Doctor/Specialist/Surgeon'],['Driver/Operator','Driver/Operator'],['Electrical/Electronic Engineer','Electrical/Electronic Engineer'],['Engineer','Engineer'],['Executive','Executive'],['Farmer','Farmer'],['Fire Brigade/Police','Fire Brigade/Police'],['Gardener/Landscaper','Gardener/Landscaper'],['Greenkeeper/Groundsperson','Greenkeeper/Groundsperson'],['HR/Recruitment','HR/Recruitment'],['Historian','Historian'],['Home Duties','Home Duties'],['Hospitality','Hospitality'],['Hotel Manager/Supervisor','Hotel Manager/Supervisor'],['IT Professional','IT Professional'],['Importer/Exporter','Importer/Exporter'],['Instructor','Instructor'],['Journalist/Proofreader','Journalist/Proofreader'],['Lab Technician','Lab Technician'],['Labourer/Factory/Process Worker','Labourer/Factory/Process Worker'],['Landscape Artist','Landscape Artist'],['Legal Officer','Legal Officer'],['Librarian','Librarian'],['Logistics','Logistics'],['Maintenance Engineer','Maintenance Engineer'],['Manager/Supervisor','Manager/Supervisor'],['Mechanic','Mechanic'],['Medical Lab Technician','Medical Lab Technician'],['Musician','Musician'],['Nurse/Midwife','Nurse/Midwife'],['Nursery and Garden Labourer','Nursery and Garden Labourer'],['Pharmacist','Pharmacist'],['Politician','Politician'],['Production','Production'],['Professional Sportsperson','Professional Sportsperson'],['Public Relations','Public Relations'],['Public Servant','Public Servant'],['Real Estate/Property','Real Estate/Property'],['Researcher','Researcher'],['Retail/Small Business Manager','Retail/Small Business Manager'],['Retired','Retired'],['Safety Inspector','Safety Inspector'],['Sales Rep','Sales Rep'],['Sales/Marketing/Advertising','Sales/Marketing/Advertising'],['Scientist/Mathematician','Scientist/Mathematician'],['Security Services/Officer','Security Services/Officer'],['Self-Employed','Self-Employed'],['Social Worker','Social Worker'],['Sole Trader','Sole Trader'],['Sound Technician','Sound Technician'],['Student','Student'],['Teacher','Teacher'],['Translator','Translator'],['Travel Agent/Consultant','Travel Agent/Consultant'],['Unemployed','Unemployed'],['University Lecturer/Teacher','University Lecturer/Teacher'],['Veterinarian','Veterinarian'],['Volunteer Work','Volunteer Work'],['Wholesale Manager','Wholesale Manager'],['Writer/Editor','Writer/Editor']];

3. Or paste the array then try to save as .js

Expected behavior: The paste/save should only take a second or two to complete.

Actual behavior: The interface hangs, a message appears asking if you would like to wait. If you click wait enough times the paste/save will complete. Each time you touch the array this introduces an additional delay. The larger the array, the larger the delay.

Reproduces how often: 100%

Versions

Atom : 1.14.3
Electron: 1.3.13
Chrome : 52.0.2743.82
Node : 6.5.0
Windows 7x64 SP1

Additional Information

Any additional information, configuration or data that might be necessary to reproduce the issue.

[winstliu]

If I remember correctly arrays are the only "bracket" structure in language-javascript that doesn't use nesting. So it seems counterintuitive that this one out of all three would be the one to have performance issues.

[helpfulBro]

Other larger arrays types e.g. Array = (string1, string2, string3); do not have the same issue. It seems specific the square brackets. Well for me anyway.

[cayetanobv]

And highlighting does not work properly. You can see screenshot:

Array example:

var arr = [[0,random(10,12,2)],[1,random(8,10,2)],[2,random(4,6,2)],[4,random(4,6,2)],[5,random(10,12,2)],[6,random(12,18,2)],[7,random(30,40,2)],[8,random(40,50,2)],[9,random(40,55,2)],[10,random(60,70,2)],[11,random(50,60,2)],[12,random(30,40,2)],[13,random(40,50,2)],[14,random(40,50,2)],[15,random(50,60,2)],[16,random(30,40,2)],[17,random(30,40,2)],[18,random(50,60,2)],[19,random(50,60,2)],[20,random(40,50,2)],[21,random(30,40,2)],[22,random(20,30,2)],[23,random(15,20,2)],[24,random(10,12,2)]];

[winstliu]

That is intentional, or else you would have a seriously bad time editing files with long lines. As in, Atom would probably crash. It is a built-in limitation to Atom's tokenizing engine.

[winstliu]

I've confirmed this as a regression after bisecting between v0.122.0 and master. @Alhadis the offending commit is 7eec645, which you committed.

EDIT: Specifically, it's the changes you made in the first half of the commit for getters and setters. It looks like the optional get/set part at the very beginning isn't that performant, because as soon as I make it required the performance is back to normal.

[Alhadis]

Sounds like a backtracking issue. Try this:

-(\\b(get|set)\\s+)?       # Property getter/setter: get foo(){}
+(\\b(get|set)\\s+)?+      # Property getter/setter: get foo(){}

EDIT: Okay, nope, that alone isn't fixing it. I'll have a closer look.

[helpfulBro]

Is there anything I can do within atom as a work around until this is included in a newer version?

[Alhadis]

@halcy0n9001 Once #494 is merged, you can link the latest changes to the package by linking it locally:

cd ~/.atom/packages
git clone https://github.com/atom/language-javascript.git

Make sure to delete it after installing the next version of Atom which includes the fix.

[helpfulBro]

@Alhadis
Thank you

[winstliu]

I'll be looking into getting this included in the next hotfix release.