(new CustomError) instanceof CustomError => false

[ken0x0a]

Maybe related to #583

(new CustomError) instanceof CustomError
// => false 
// should be `true` but will get `false` @ ts-node
// `true` @ node

In addition, constructor also works unexpectedly.

(new WithoutConstructorError).constructor === WithoutConstructorError // => false
(new WithoutConstructorError).constructor === Error // => true

I've tested using following code.
Adding constructor in class did not change result.

class WithoutConstructorError extends Error {}

(new Error).name
(new WithoutConstructorError).name

(new Error) instanceof Error
(new Error) instanceof WithoutConstructorError
(new WithoutConstructorError) instanceof WithoutConstructorError
(new WithoutConstructorError) instanceof Error

(new Error).constructor === Error
(new Error).constructor === WithoutConstructorError
(new WithoutConstructorError).constructor === WithoutConstructorError
(new WithoutConstructorError).constructor === Error

[blakeembrey]

I think this may be related to your target ES version, but I’ll investigate more when I have a chance. Are you specifying a custom target at all?

[iam4x]

I was having a similar issue, narrowed it down to nodejs itself! Might be relevant nodejs/node#27859 ?

[ken0x0a]

@blakeembrey Thank you for your reply!

I'm sorry I didn't notice.

Actually I didn't understand what you mean, but I tried target ES versions (es5, es2015, es2018), and got same result.

With following configuration

    "target": "es5"
    "module": "commonjs"

> class WithoutConstructorError extends Error {}
'use strict'
>
undefined
> (new Error).name
'Error'
> (new WithoutConstructorError).name
'Error'
>

With following configuration also same result

    "target": "es2015" or "es2018"
    "module": "commonjs"

[ken0x0a]

@iam4x Thank you for your reply!

Since I got expected result @ node, I guess that is not the something.

[davoam]

I think this may be related to your target ES version, but I’ll investigate more when I have a chance. Are you specifying a custom target at all?

In my case changing target from es5 to es2018 helped.

Also take a look at this issue microsoft/TypeScript#10166

[blakeembrey]

Thanks @davoam, I'm going to close this issue since it's most likely related to emitted output. It's a reason I've always used something like https://www.npmjs.com/package/make-error in custom projects.