Skip to content

Do not parse template arguments in JavaScript files. - #36673

Merged
Andrew Branch (andrewbranch) merged 1 commit into
microsoft:masterfrom
mprobst:parse-js
Nov 19, 2020
Merged

Do not parse template arguments in JavaScript files.#36673
Andrew Branch (andrewbranch) merged 1 commit into
microsoft:masterfrom
mprobst:parse-js

Conversation

@mprobst

@mprobstMartin Probst (mprobst) commented Feb 7, 2020

Copy link
Copy Markdown
Contributor

Fixes#36662.

This is somewhat preliminary. The main drawback of the change is that users will get substantially worse error messages if they accidentally include <Type, Arguments> in JavaScript files (see the associated errors.txt changes).

To mitigate, we could:

  1. keep parsing type arguments in JSX element contexts (<Element<Type, Arg> x=1>). I don't think this is ambiguous with any JS syntax.
  2. attempt to special case and pass down a flag to produce a better error message for code like fnCall<Type, Argument>()

(2) could be tricky to get right enough to really improve developer's life, so I think whether it's worth doing depends on how likely we think the scenario is in the first place.

@fatcerberus

Bruce Pascoe (fatcerberus) commented Feb 9, 2020•
edited
Loading

Copy link
Copy Markdown

users will get substantially worse error messages if they accidentally include <Type, Arguments> in JavaScript files

Worse, they may get no error message if they accidentally include a single <TypeArgument> (particularly in the case that the type argument has representation in value space, e.g. a class) because that will now be parsed as a less-than operator followed by greater-than operator. Unfortunately there's no heuristic that would be able to tell the difference with 100% accuracy 😦

@mprobst

Martin Probst (mprobst) commented Feb 12, 2020

Copy link
Copy Markdown
ContributorAuthor

Bruce Pascoe (@fatcerberus) ack, but that's fundamentally because in JS, foo<TypeArgument>(bar) has a defined and standardized meaning as comparison operations. I think it's ultimately less confusing to be correct according to the spec here rather than being incorrect with better error messages.

@sandersnNathan Shively-Sanders (sandersn) added the For Backlog Bug PRs that fix a backlog bug label Feb 14, 2020
@andrewbranchAndrew Branch (andrewbranch) added the Breaking Change Would introduce errors in existing code label Apr 1, 2020
@andrewbranch

Andrew Branch (andrewbranch) commented Apr 1, 2020

Copy link
Copy Markdown
Member

Tentatively filing this as a breaking change even though that’s sort of debatable. Most of the time this is going to be swapping one error for another; very occasionally it will be removing an undesired error (which is the point of the PR, #36662), but as Bruce Pascoe (@fatcerberus) pointed out, there could be a possible scenario where you were getting a desired error (type arguments can’t be used in JS) before, and aren’t now.

I’d like to dig into the specifics of whether that could actually ever happen without getting a new error in the vein of “Operator '<' cannot be applied to types...” I guess if enough of the variables in play are declared as any, that would do the trick.

@andrewbranch

Andrew Branch (andrewbranch) commented Apr 1, 2020

Copy link
Copy Markdown
Member

keep parsing type arguments in JSX element contexts

Also FWIW, I do think this would be an easy win if it’s not ambiguous.

@DanielRosenwasser

Daniel Rosenwasser (DanielRosenwasser) commented Apr 1, 2020

Copy link
Copy Markdown
Member

For checkJs, you'll get a bad error - but we can potentially do some gymnastics to figure it out. The real break is for API consumers.

@andrewbranch

Andrew Branch (andrewbranch) commented Apr 1, 2020•
edited
Loading

Copy link
Copy Markdown
Member

For checkJs, you'll get a bad error

But not when a bunch of stuff is any 😕. This would become error-free: https://www.typescriptlang.org/play?noImplicitAny=false&useJavaScript=true#code/MYGwhgzhAEAqCeAHApgQQE4HMCuBbZAdgC7QDeAvgFCUBm2BwRAlgPYHQ0AUNLLANNABGYdAEoylaFOjpkRbOnY8WAHgQoMOfMQB8nYWIDclKkA

@DanielRosenwasser

Daniel Rosenwasser (DanielRosenwasser) commented Apr 1, 2020

Copy link
Copy Markdown
Member

Well shame on you for having anys!

@DanielRosenwasser

Daniel Rosenwasser (DanielRosenwasser) commented Apr 1, 2020

Copy link
Copy Markdown
Member

Jokes aside, I think I'd be surprised to see a user write explicit type arguments in a JS file that's unchecked. TypeScript users already see explicit type arguments as a bit of a code smell.

@sandersn

Nathan Shively-Sanders (sandersn) commented Apr 2, 2020

Copy link
Copy Markdown
Member

One possible exception is .js files that are flow-checked. I'm not sure whether there are more of those than of .js files with syntax that is currently parsing as type arguments.

@DanielRosenwasser

Daniel Rosenwasser (DanielRosenwasser) commented Apr 3, 2020

Copy link
Copy Markdown
Member

TypeScript Bot (@typescript-bot) pack this

@typescript-bot

TypeScript Bot (typescript-bot) commented Apr 3, 2020•
edited
Loading

Copy link
Copy Markdown
Contributor

Heya Daniel Rosenwasser (@DanielRosenwasser), I've started to run the tarball bundle task on this PR at f308ac1. You can monitor the build here.

@DanielRosenwasser

Daniel Rosenwasser (DanielRosenwasser) commented Apr 3, 2020

Copy link
Copy Markdown
Member

Just want to make sure we still give good errors on

  • type parameters function declarations and expressions
  • type parameters arrow functions
  • and type references

Maybe Brian Terlson (@bterlson) can help find examples that are valid JS we also currently have issues with

Closed
@DanielRosenwasser

Daniel Rosenwasser (DanielRosenwasser) commented Jul 10, 2020

Copy link
Copy Markdown
Member

TypeScript Bot (@typescript-bot) pack this
TypeScript Bot (@typescript-bot) test this
TypeScript Bot (@typescript-bot) user test this
TypeScript Bot (@typescript-bot) run dt
TypeScript Bot (@typescript-bot) perf test this

@typescript-bot

TypeScript Bot (typescript-bot) commented Jul 10, 2020•
edited
Loading

Copy link
Copy Markdown
Contributor

Heya Daniel Rosenwasser (@DanielRosenwasser), I've started to run the parallelized Definitely Typed test suite on this PR at f308ac1. You can monitor the build here.

@typescript-bot

TypeScript Bot (typescript-bot) commented Jul 10, 2020•
edited
Loading

Copy link
Copy Markdown
Contributor

Heya Daniel Rosenwasser (@DanielRosenwasser), I've started to run the tarball bundle task on this PR at f308ac1. You can monitor the build here.

@typescript-bot

TypeScript Bot (typescript-bot) commented Jul 10, 2020•
edited
Loading

Copy link
Copy Markdown
Contributor

Heya Daniel Rosenwasser (@DanielRosenwasser), I've started to run the parallelized community code test suite on this PR at f308ac1. You can monitor the build here.

@typescript-bot

TypeScript Bot (typescript-bot) commented Jul 10, 2020•
edited
Loading

Copy link
Copy Markdown
Contributor

Heya Daniel Rosenwasser (@DanielRosenwasser), I've started to run the perf test suite on this PR at f308ac1. You can monitor the build here.

Update: The results are in!

@typescript-bot

TypeScript Bot (typescript-bot) commented Jul 10, 2020•
edited
Loading

Copy link
Copy Markdown
Contributor

Heya Daniel Rosenwasser (@DanielRosenwasser), I've started to run the extended test suite on this PR at f308ac1. You can monitor the build here.

@typescript-bot

TypeScript Bot (typescript-bot) commented Jul 10, 2020

Copy link
Copy Markdown
Contributor

Daniel Rosenwasser (@DanielRosenwasser)
The results of the perf run you requested are in!

Here they are:

Comparison Report - master..36673

Metricmaster36673DeltaBestWorst
Angular - node (v10.16.3, x64)
Memory used343,962k (± 0.01%)343,423k (± 0.01%)-540k (- 0.16%)343,333k343,543k
Parse Time2.00s (± 0.50%)2.02s (± 0.70%)+0.01s (+ 0.60%)2.00s2.06s
Bind Time0.81s (± 0.64%)0.82s (± 0.54%)+0.01s (+ 0.86%)0.81s0.83s
Check Time4.73s (± 0.29%)4.74s (± 0.80%)+0.01s (+ 0.23%)4.64s4.79s
Emit Time5.19s (± 0.59%)5.21s (± 1.48%)+0.02s (+ 0.42%)5.12s5.51s
Total Time12.73s (± 0.25%)12.78s (± 0.87%)+0.05s (+ 0.40%)12.65s13.19s
Monaco - node (v10.16.3, x64)
Memory used339,143k (± 0.03%)339,267k (± 0.03%)+124k (+ 0.04%)339,064k339,415k
Parse Time1.58s (± 0.55%)1.58s (± 0.92%)+0.00s (+ 0.32%)1.55s1.61s
Bind Time0.71s (± 0.78%)0.72s (± 0.51%)+0.00s (+ 0.56%)0.71s0.72s
Check Time4.91s (± 0.64%)4.89s (± 0.64%)-0.01s (- 0.29%)4.83s4.95s
Emit Time2.74s (± 0.35%)2.74s (± 0.83%)-0.00s (- 0.11%)2.69s2.80s
Total Time9.95s (± 0.32%)9.94s (± 0.49%)-0.01s (- 0.08%)9.80s10.02s
TFS - node (v10.16.3, x64)
Memory used302,064k (± 0.02%)302,062k (± 0.02%)-2k (- 0.00%)301,968k302,186k
Parse Time1.20s (± 0.68%)1.22s (± 0.67%)+0.01s (+ 1.16%)1.20s1.24s
Bind Time0.66s (± 1.03%)0.67s (± 1.02%)+0.00s (+ 0.15%)0.65s0.68s
Check Time4.39s (± 0.39%)4.42s (± 0.82%)+0.03s (+ 0.78%)4.35s4.49s
Emit Time2.89s (± 0.92%)2.88s (± 0.69%)-0.01s (- 0.48%)2.82s2.91s
Total Time9.15s (± 0.40%)9.18s (± 0.37%)+0.03s (+ 0.34%)9.12s9.26s
material-ui - node (v10.16.3, x64)
Memory used459,445k (± 0.01%)459,143k (± 0.01%)-303k (- 0.07%)459,034k459,262k
Parse Time2.04s (± 0.29%)2.04s (± 0.40%)-0.00s (- 0.05%)2.02s2.06s
Bind Time0.65s (± 1.88%)0.65s (± 1.57%)0.00s ( 0.00%)0.63s0.67s
Check Time12.93s (± 0.92%)12.85s (± 0.78%)-0.07s (- 0.57%)12.72s13.21s
Emit Time0.00s (± 0.00%)0.00s (± 0.00%)0.00s ( NaN%)0.00s0.00s
Total Time15.62s (± 0.75%)15.55s (± 0.67%)-0.07s (- 0.46%)15.39s15.92s
Angular - node (v12.1.0, x64)
Memory used320,857k (± 0.13%)320,761k (± 0.02%)-96k (- 0.03%)320,601k320,882k
Parse Time1.98s (± 0.60%)1.99s (± 0.56%)+0.01s (+ 0.71%)1.97s2.02s
Bind Time0.80s (± 1.34%)0.80s (± 0.42%)+0.00s (+ 0.25%)0.80s0.81s
Check Time4.63s (± 0.83%)4.66s (± 0.56%)+0.03s (+ 0.69%)4.62s4.74s
Emit Time5.37s (± 1.29%)5.36s (± 0.64%)-0.01s (- 0.19%)5.31s5.44s
Total Time12.78s (± 0.75%)12.82s (± 0.22%)+0.03s (+ 0.26%)12.77s12.89s
Monaco - node (v12.1.0, x64)
Memory used321,581k (± 0.02%)321,575k (± 0.03%)-6k (- 0.00%)321,394k321,817k
Parse Time1.54s (± 0.99%)1.56s (± 0.48%)+0.02s (+ 1.10%)1.54s1.57s
Bind Time0.69s (± 1.40%)0.69s (± 0.99%)+0.01s (+ 0.87%)0.69s0.72s
Check Time4.65s (± 1.27%)4.68s (± 0.37%)+0.03s (+ 0.62%)4.64s4.73s
Emit Time2.78s (± 1.48%)2.79s (± 0.42%)+0.02s (+ 0.61%)2.77s2.82s
Total Time9.66s (± 1.21%)9.73s (± 0.20%)+0.07s (+ 0.67%)9.68s9.76s
TFS - node (v12.1.0, x64)
Memory used286,569k (± 0.01%)286,574k (± 0.03%)+5k (+ 0.00%)286,459k286,772k
Parse Time1.23s (± 0.74%)1.24s (± 0.66%)+0.01s (+ 0.49%)1.22s1.26s
Bind Time0.64s (± 0.81%)0.64s (± 0.90%)+0.00s (+ 0.63%)0.63s0.65s
Check Time4.30s (± 0.59%)4.32s (± 0.58%)+0.02s (+ 0.44%)4.26s4.38s
Emit Time2.92s (± 0.80%)2.94s (± 1.25%)+0.02s (+ 0.82%)2.89s3.05s
Total Time9.09s (± 0.46%)9.14s (± 0.38%)+0.05s (+ 0.57%)9.07s9.22s
material-ui - node (v12.1.0, x64)
Memory used437,822k (± 0.01%)437,380k (± 0.07%)-441k (- 0.10%)436,236k437,679k
Parse Time2.04s (± 0.88%)2.04s (± 0.29%)-0.00s (- 0.10%)2.02s2.05s
Bind Time0.64s (± 0.94%)0.63s (± 0.82%)-0.00s (- 0.63%)0.62s0.64s
Check Time11.65s (± 0.72%)11.61s (± 0.79%)-0.04s (- 0.31%)11.43s11.85s
Emit Time0.00s (± 0.00%)0.00s (± 0.00%)0.00s ( NaN%)0.00s0.00s
Total Time14.32s (± 0.55%)14.28s (± 0.66%)-0.04s (- 0.29%)14.08s14.52s
Angular - node (v8.9.0, x64)
Memory used340,444k (± 0.01%)340,091k (± 0.01%)-352k (- 0.10%)339,972k340,191k
Parse Time2.53s (± 0.27%)2.53s (± 0.37%)+0.00s (+ 0.04%)2.51s2.54s
Bind Time0.85s (± 0.58%)0.85s (± 0.70%)-0.01s (- 0.94%)0.83s0.86s
Check Time5.35s (± 0.46%)5.36s (± 0.52%)+0.01s (+ 0.09%)5.30s5.42s
Emit Time5.90s (± 1.08%)5.96s (± 1.13%)+0.06s (+ 0.97%)5.87s6.15s
Total Time14.64s (± 0.51%)14.69s (± 0.46%)+0.05s (+ 0.37%)14.57s14.84s
Monaco - node (v8.9.0, x64)
Memory used340,492k (± 0.01%)340,497k (± 0.01%)+5k (+ 0.00%)340,379k340,609k
Parse Time1.87s (± 0.43%)1.87s (± 0.40%)+0.00s (+ 0.11%)1.86s1.89s
Bind Time0.88s (± 0.25%)0.88s (± 0.77%)+0.00s (+ 0.34%)0.87s0.90s
Check Time5.40s (± 0.62%)5.41s (± 0.43%)+0.01s (+ 0.19%)5.36s5.45s
Emit Time3.22s (± 0.37%)3.23s (± 0.56%)+0.01s (+ 0.25%)3.19s3.27s
Total Time11.37s (± 0.36%)11.40s (± 0.37%)+0.03s (+ 0.23%)11.33s11.47s
TFS - node (v8.9.0, x64)
Memory used303,833k (± 0.02%)303,847k (± 0.02%)+15k (+ 0.00%)303,752k303,972k
Parse Time1.54s (± 0.48%)1.54s (± 0.53%)-0.00s (- 0.00%)1.53s1.56s
Bind Time0.67s (± 0.77%)0.67s (± 0.71%)-0.00s (- 0.60%)0.66s0.68s
Check Time5.03s (± 1.38%)4.94s (± 0.95%)-0.09s (- 1.79%)4.85s5.09s
Emit Time3.03s (± 2.64%)3.13s (± 1.85%)+0.10s (+ 3.14%)2.91s3.22s
Total Time10.27s (± 0.35%)10.28s (± 0.39%)+0.00s (+ 0.03%)10.21s10.39s
material-ui - node (v8.9.0, x64)
Memory used463,640k (± 0.01%)463,426k (± 0.01%)-214k (- 0.05%)463,334k463,499k
Parse Time2.41s (± 0.34%)2.40s (± 0.70%)-0.02s (- 0.75%)2.36s2.43s
Bind Time0.78s (± 0.85%)0.77s (± 0.96%)-0.01s (- 1.66%)0.76s0.79s
Check Time17.19s (± 1.33%)17.11s (± 1.13%)-0.08s (- 0.46%)16.59s17.49s
Emit Time0.00s (± 0.00%)0.00s (± 0.00%)0.00s ( NaN%)0.00s0.00s
Total Time20.39s (± 1.12%)20.28s (± 1.02%)-0.11s (- 0.53%)19.73s20.71s
Angular - node (v8.9.0, x86)
Memory used195,323k (± 0.03%)195,070k (± 0.01%)-253k (- 0.13%)195,004k195,116k
Parse Time2.45s (± 0.82%)2.47s (± 1.17%)+0.02s (+ 0.82%)2.42s2.56s
Bind Time0.99s (± 0.62%)0.99s (± 0.66%)-0.00s (- 0.10%)0.97s1.00s
Check Time4.83s (± 0.84%)4.87s (± 1.02%)+0.03s (+ 0.68%)4.79s5.01s
Emit Time5.95s (± 1.07%)5.93s (± 1.13%)-0.02s (- 0.27%)5.77s6.08s
Total Time14.22s (± 0.67%)14.26s (± 0.82%)+0.04s (+ 0.26%)14.06s14.62s
Monaco - node (v8.9.0, x86)
Memory used193,511k (± 0.02%)193,501k (± 0.03%)-10k (- 0.01%)193,355k193,640k
Parse Time1.92s (± 0.99%)1.91s (± 0.46%)-0.02s (- 0.88%)1.88s1.92s
Bind Time0.70s (± 0.43%)0.70s (± 1.43%)+0.01s (+ 0.86%)0.69s0.74s
Check Time5.50s (± 0.48%)5.49s (± 0.47%)-0.01s (- 0.18%)5.43s5.55s
Emit Time2.68s (± 0.65%)2.68s (± 0.96%)+0.00s (+ 0.11%)2.63s2.74s
Total Time10.80s (± 0.38%)10.78s (± 0.40%)-0.02s (- 0.17%)10.66s10.86s
TFS - node (v8.9.0, x86)
Memory used173,771k (± 0.01%)173,763k (± 0.02%)-8k (- 0.00%)173,678k173,874k
Parse Time1.58s (± 0.67%)1.61s (± 1.15%)+0.03s (+ 2.03%)1.57s1.65s
Bind Time0.64s (± 1.01%)0.65s (± 1.05%)+0.01s (+ 1.25%)0.64s0.67s
Check Time4.68s (± 0.79%)4.69s (± 0.55%)+0.01s (+ 0.15%)4.63s4.75s
Emit Time2.80s (± 1.33%)2.82s (± 1.10%)+0.02s (+ 0.54%)2.73s2.87s
Total Time9.70s (± 0.56%)9.76s (± 0.52%)+0.06s (+ 0.60%)9.63s9.89s
material-ui - node (v8.9.0, x86)
Memory used262,544k (± 0.02%)262,408k (± 0.02%)-136k (- 0.05%)262,299k262,499k
Parse Time2.45s (± 0.47%)2.47s (± 0.78%)+0.03s (+ 1.06%)2.44s2.53s
Bind Time0.67s (± 1.91%)0.67s (± 1.26%)+0.00s (+ 0.45%)0.66s0.69s
Check Time15.67s (± 0.51%)15.66s (± 0.74%)-0.01s (- 0.06%)15.45s15.91s
Emit Time0.00s (± 0.00%)0.00s (± 0.00%)0.00s ( NaN%)0.00s0.00s
Total Time18.79s (± 0.40%)18.80s (± 0.57%)+0.02s (+ 0.09%)18.60s19.02s
System
Machine Namets-ci-ubuntu
Platformlinux 4.4.0-166-generic
Architecturex64
Available Memory16 GB
Available Memory1 GB
CPUs4 × Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz
Hosts
  • node (v10.16.3, x64)
  • node (v12.1.0, x64)
  • node (v8.9.0, x64)
  • node (v8.9.0, x86)
Scenarios
  • Angular - node (v10.16.3, x64)
  • Angular - node (v12.1.0, x64)
  • Angular - node (v8.9.0, x64)
  • Angular - node (v8.9.0, x86)
  • Monaco - node (v10.16.3, x64)
  • Monaco - node (v12.1.0, x64)
  • Monaco - node (v8.9.0, x64)
  • Monaco - node (v8.9.0, x86)
  • TFS - node (v10.16.3, x64)
  • TFS - node (v12.1.0, x64)
  • TFS - node (v8.9.0, x64)
  • TFS - node (v8.9.0, x86)
  • material-ui - node (v10.16.3, x64)
  • material-ui - node (v12.1.0, x64)
  • material-ui - node (v8.9.0, x64)
  • material-ui - node (v8.9.0, x86)
BenchmarkNameIterations
Current3667310
Baselinemaster10

@DanielRosenwasserDaniel Rosenwasser (DanielRosenwasser) added the Domain: API Relates to the public API for TypeScript label Nov 19, 2020
andrewbranch
Andrew Branch (andrewbranch) approved these changes Nov 19, 2020
View reviewed changes

@andrewbranchAndrew Branch (andrewbranch) left a comment

Copy link
Copy Markdown
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Thanks for your patience, everyone. I think we should take this 🌟

@DanielRosenwasser

Daniel Rosenwasser (DanielRosenwasser) commented Nov 19, 2020

Copy link
Copy Markdown
Member

Marking this with the API label just because if you were ever using TS to parse Flow-y code, you're now going to have issues.

@andrewbranch
Andrew Branch (andrewbranch) merged commit 6b04f50 into microsoft:masterNov 19, 2020
@andrewbranchAndrew Branch (andrewbranch) mentioned this pull request Nov 19, 2020
Merged
@mprobst
Martin Probst (mprobst) deleted the parse-js branch June 15, 2021 10:08
@microsoftMicrosoft (microsoft) locked as resolved and limited conversation to collaborators Oct 21, 2025
Sign up for freeto subscribe to this conversation on GitHub. Already have an account? Sign in.

Reviewers

@andrewbranchAndrew Branch (andrewbranch)andrewbranch approved these changes

Assignees

@andrewbranchAndrew Branch (andrewbranch)

Labels

Breaking ChangeWould introduce errors in existing codeDomain: APIRelates to the public API for TypeScriptFor Backlog BugPRs that fix a backlog bug

Projects

PR Backlog
Archived in project

Milestone

No milestone

Development

Successfully merging this pull request may close these issues.

JS value being parsed as a TS type argument

6 participants

@mprobst@fatcerberus@andrewbranch@DanielRosenwasser@sandersn@typescript-bot