catch.go raw

   1  //go:build js && wasm
   2  
   3  // Package catch runs functions and returns panic values as errors instead.
   4  package catch
   5  
   6  import (
   7  	"fmt"
   8  	"syscall/js"
   9  
  10  	"github.com/hack-pad/safejs/internal/stackerr"
  11  )
  12  
  13  // Try runs fn and returns the result. If fn panicked, the panic value is returned as an error instead.
  14  func Try[Result any](fn func() Result) (result Result, err error) {
  15  	defer recoverErr(&err)
  16  	result = fn()
  17  	return
  18  }
  19  
  20  // TrySideEffect is like Try, but does not have a return value.
  21  func TrySideEffect(fn func()) (err error) {
  22  	defer recoverErr(&err)
  23  	fn()
  24  	return
  25  }
  26  
  27  func recoverErr(err *error) {
  28  	value := recover()
  29  	valueErr := recoverValueToError(value)
  30  	if valueErr != nil {
  31  		*err = stackerr.WithStack(valueErr)
  32  	}
  33  }
  34  
  35  func recoverValueToError(value any) error {
  36  	if value == nil {
  37  		return nil
  38  	}
  39  	switch value := value.(type) {
  40  	case error:
  41  		return value
  42  	case js.Value:
  43  		return js.Error{Value: value}
  44  	default:
  45  		return fmt.Errorf("%+v", value)
  46  	}
  47  }
  48