Methods are not ignored in mapped types (maked with keyof syntax) about typescript-is HOT 5 CLOSED

The new option ignoreFunctions has solved my problem. Thanks so much

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Hi @SteMab

There are two things going on that are causing the issue:

1. When you write type MappedType = { [P in keyof MyClass]: MyClass[P]; }, TypeScript does not keep method as an actual method. Instead, it becomes a regular object property with a function type. You can see this if you inspect the type MappedType, it will have the property method as a function: method: () => string.

2. Because of this, ignoreMethods will not be checked to decide to ignore this property. typescript-is is now working with a regular function, and because these are not supported, its behavior is undefined.

To solve this:

1. I can add a new option ignoreFunctions with similar behavior as ignoreMethods but will work for any function.

2. You can avoid using assertType on classes/functions/methods. Since you have a class instance, why not use instanceof?

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@woutervh- Thank you for your kind reply which clarified the point.
I can't use instanceof because I'm writing an http firebase function and the object to check was been serialized.

An option ignoreFunctions would be useful, in my opinion (but I'm not familiar with typescript and prototype-based programming).

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Hi @SteMab

I've added the option ignoreFunctions:
https://github.com/woutervh-/typescript-is/releases/tag/v0.14.3
https://github.com/woutervh-/typescript-is#options

Let me know if this helps :)

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Found this from the link in the error message and want to leave a note that ignoreFunctions is deprecated and you can now declare functionBehavior: "basic" instead.

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