TS1108 "problem" showing on pure Javascript (node) file - Erroneous Error Flag

[robertblum-psi]

Issue Type: Bug

PROBLEMS pane shows:
[JS] file.js (1)
A 'return' statement can only be used within a function body. ts(1108) [400,5]

My node Javascript file is statements that call defined functions. These statements have an if statement that executes a return statement when true. The program is Javascript, and recognized as such by editor. There is no typescript in the environment. This bug appeared immediately after VS Code updated to February 2022 version (1.65.2). It did not appear in the previous version with the exact same file. The program runs properly on the target when run.

UPDATE: I have installed 1.64.2 to remediate issue. The problem does not occur down-level.

The program looks like this:

#!/usr/bin/env node
statements and function definitions
if ( x == y)
return
statements

A Typescript error should not show for a Javascript file.

VS Code version: Code 1.65.2 (c722ca6c7eed3d7987c0d5c3df5c45f6b15e77d1, 2022-03-10T14:33:55.248Z)
OS version: Windows_NT x64 10.0.19043
Restricted Mode: No

System Info

Item	Value
CPUs	Intel(R) Core(TM) i7-6770HQ CPU @ 2.60GHz (8 x 2592)
GPU Status	2d_canvas: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on oop_rasterization: enabled opengl: enabled_on rasterization: enabled skia_renderer: enabled_on video_decode: enabled vulkan: disabled_off webgl: enabled webgl2: enabled
Load (avg)	undefined
Memory (System)	31.89GB (23.34GB free)
Process Argv
Screen Reader	no
VM	0%

Extensions (11)

Extension	Author (truncated)	Version
Bookmarks	ale	13.2.4
bracket-pair-colorizer	Coe	1.0.62
html-preview-vscode	geo	0.2.5
vscode-pull-request-github	Git	0.38.1
ibm-jcl	kel	0.11.0
remote-wsl	ms-	0.64.2
rexx	nex	0.0.1
deepdark-material	Nim	3.3.0
ayu	tea	1.0.5
pdf	tom	1.2.0
vscode-extension-for-zowe	Zow	1.22.0

(17 theme extensions excluded)

A/B Experiments

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pynewfile477:30450038

[mjbvz]

@sandersn Looks like node does allow top level returns so we may want to exclude this from the default JS syntax checks

@robertblum-psi This was added in 1.65, see https://code.visualstudio.com/updates/v1_65#_syntax-error-reporting-in-javascript-files for details and how you can disable this

[robertblum-psi]

@mjbvz

@robertblum-psi This was added in 1.65, see https://code.visualstudio.com/updates/v1_65#_syntax-error-reporting-in-javascript-files for details and how you can disable this

Javascript and Nodejs are not Typescript, and have their own conception of typing that is often radically different than Typescript's. It is a bad idea to enable this for Javascript by default. This change needs to be reverted.

[mjbvz]

@robertblum-psi This is not related to TS vs JS

These new checks enabled for JavaScript assumed that top level return statements are always a mistake (because in most JS environments they are). However it looks like node sometimes allows them, so we likely don't want to enable this specific check by default

Worth noting that returns are still invalid in node if the file is a module and using them goes against the JS spec afaik

[robertblum-psi]

@mjbvz
I consider the setting "javascript.validate.enable" to be misleading. Because it turns on Typescript-like validation, it ought to be named javascript.typescriptvalidate.enable instead.

[robertblum-psi]

@mjbvz:

... assumed that top level return statements are always a mistake (because in most JS environments they are). However it looks like node sometimes allows them...

Node always does AFAIK. JS and Nodejs are very flexible.

It occurs to me that some thought then ought to be given to a node flavor of Javascript, like there is one for REACT. I am not advocating this. I would much rather that there be no Typescript checks on Javascript code, full stop.

[fatcerberus]

The checks that have been enabled are not typing related (that’s what checkJs is for). They are (intended to be) for semantic/syntax errors that will cause an issue at runtime but were too complex to detect in the parser. For example, previously this wasn’t caught as an error in JS files despite being a syntax error at runtime:

const foo = {
    foo = 1,
    bar = 2,
}

now it is. These kinds of checks are a good thing.

[MartinJohns]

I would much rather that there be no Typescript checks on Javascript code, full stop.

Does the mentioned setting not work for you?