go - Adding a method for existing type in Golang: how to rewrite return value's type -

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i want extend existing goquery.selection type own method , able use package's selectors. know cannot "patch" existing method -- need create new one. how can force existing package functions use new type? i'm missing in general or there's no "nice" way , it's better use function?

package main  import (     "fmt"     "github.com/puerkitobio/goquery" )  type customselection goquery.selection  func (s *customselection) custommethod() int {     return 1 }  doc.find("*").each(func(i int, s *goquery.selection) {   fmt.println(s.custommethod())  // not works since still "goquery.selection"   // how can result customselection type here?  })

since inheritance not supported, best practice embed non-local type own local type, , extend it.

in design patterns lingo better known composition: https://en.wikipedia.org/wiki/composition_over_inheritance


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