Fix abstract coder filter and map types

[KillariDev]

when running ethers with following libs & versions:
"better-typescript-lib": "2.6.0"
"typescript": "5.3.3"

I get following errors:

node_modules/ethers/lib.esm/abi/coders/abstract-coder.d.ts:41:5 - error TS2416: Property 'filter' in type 'Result' is not assignable to the same property in base type 'any[]'.
  Type '(callback: (el: any, index: number, array: Result) => boolean, thisArg?: any) => Result' is not assignable to type '{ <S extends any, This = undefined>(predicate: (this: This, value: any, index: number, array: this) => value is S, thisArg?: This | undefined): S[]; <This = undefined>(predicate: (this: This, value: any, index: number, array: this) => boolean, thisArg?: This | undefined): any[]; }'.
    Types of parameters 'callback' and 'predicate' are incompatible.
      Type '(this: any, value: any, index: number, array: this) => value is any' is not assignable to type '(el: any, index: number, array: Result) => boolean'.
        Types of parameters 'array' and 'array' are incompatible.
          Type 'Result' is not assignable to type 'this'.
            'Result' is assignable to the constraint of type 'this', but 'this' could be instantiated with a different subtype of constraint 'Result'.

41     filter(callback: (el: any, index: number, array: Result) => boolean, thisArg?: any): Result;
       ~~~~~~

node_modules/ethers/lib.esm/abi/coders/abstract-coder.d.ts:45:5 - error TS2416: Property 'map' in type 'Result' is not assignable to the same property in base type 'any[]'.
  Type '<T extends unknown = any>(callback: (el: any, index: number, array: Result) => T, thisArg?: any) => T[]' is not assignable to type '<U, This = undefined>(callbackfn: (this: This, value: any, index: number, array: this) => U, thisArg?: This | undefined) => Cast<{ [K in keyof this]: U; }, U[]>'.
    Types of parameters 'callback' and 'callbackfn' are incompatible.
      Types of parameters 'array' and 'array' are incompatible.
        Type 'Result' is not assignable to type 'this'.
          'Result' is assignable to the constraint of type 'this', but 'this' could be instantiated with a different subtype of constraint 'Result'.

45     map<T extends any = any>(callback: (el: any, index: number, array: Result) => T, thisArg?: any): Array<T>;
       ~~~

This pr fixes this typing issue

[ricmoo]

What is the root cause of the type issue? Were the node definitions changed in types?

I worry about making these sorts of changes as Ethers is widely used and so backwards compatibility is a hard requirement and changes that could break (even obscure) environments cannot be made…

[KillariDev]

What is the root cause of the type issue? Were the node definitions changed in types?

I worry about making these sorts of changes as Ethers is widely used and so backwards compatibility is a hard requirement and changes that could break (even obscure) environments cannot be made…

This makes the map and filter types more strict and more accurate. Its true that it can break backward compatibility, maybe worth fixing for never version.

However, seems like this is a bigger can of worms than I initially thought. The type of array.map is complex. See this discussion: uhyo/better-typescript-lib#35 . And it seems like there's recommendation that array overrides should not be used as they can be security vulnerabilities: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/@@species

So I think in newer ethers versions, this array overloading should be removed all together?

[ricmoo]

Yes, in the v7 branch (local only) I don't override any of the Array method. I've got a whole different (less-intrusive) way to expose the Array as a keyed value as well, using a combination of WeakMaps and the Proxy. :)