js/ts.implicitProjectConfig.checkJs error underlining something as not working, but it is

[1Euro7Cent]

Does this issue occur when all extensions are disabled?: Yes

• Version: 1.74.0 (user setup)
  Commit: 5235c6b
  Date: 2022-12-05T16:38:16.075Z
  Electron: 19.1.8
  Chromium: 102.0.5005.167
  Node.js: 16.14.2
  V8: 10.2.154.15-electron.0
  OS: Windows_NT x64 10.0.19044
  Sandboxed: No

Steps to Reproduce:

1. have "js/ts.implicitProjectConfig.checkJs": true, in the settings.json
2. have the following block in a .js file:

const b = "something"

class A {
    constructor() {
        this.b = "something"
    }
    toString() {
        return this.b
    }
}
let a = new A()
if (a == b) { // it undelines this with error: This comparison appears to be unintentional because the types 'A' and 'string' have no overlap.
    console.log("it is true")
}
else {
    console.log("it is false")
}

when I run it I get it is true in the console

It seems like it does not check if there is a toString function in that class. In boolean comparisons NodeJS autocalls that function before comparing.

[IllusionMH]

TS doesn't work nicely with non-strict equal, and also doesn't use toString or valueOf. (see microsoft/TypeScript#2361)

[mjbvz]

Closing as upstream

(Honestly you should probably refactor any code that does this though)