Use reference to Eval to judge if it's nil

Author: otiai10

binding.go

@@ -16,7 +16,7 @@ type Binding struct {
 	ValueFrom  *Alias `json:"valueFrom"`
 	// CommandOutputBinding
 	Glob     []string `json:"glob"`
-	Eval     Eval     `json:"outputEval"`
+	Eval     *Eval    `json:"outputEval"`
 	Contents bool     `json:"loadContents"`
 }
 
@@ -42,7 +42,7 @@ func (binding Binding) New(i interface{}) *Binding {
 			case "valueFrom":
 				dest.ValueFrom = &Alias{v.(string)}
 			case "outputEval":
-				dest.Eval = Eval{v.(string)}
+				dest.Eval = &Eval{v.(string)}
 			}
 		}
 	}

output.go

@@ -145,17 +145,39 @@ func (outs Outputs) LoadContents(srcdir string) (*otto.Otto, error) {
 // Dump ...
 func (outs Outputs) Dump(vm *otto.Otto, dir string, stdout, stderr string, w io.Writer) error {
 
-	dest := map[string]map[string]interface{}{}
+	dest := map[string]interface{}{}
 	for _, o := range outs {
+		if o.Binding != nil && o.Binding.Eval != nil && vm != nil {
+			js, err := o.Binding.Eval.ToJavaScriptString()
+			if err != nil {
+				return err
+			}
+			v, err := vm.Run(js)
+			if err != nil {
+				return err
+			}
+			switch {
+			case v.IsNumber():
+				dest[o.ID], err = v.ToInteger()
+				if err != nil {
+					return err
+				}
+			default:
+				// TODO: more type switch
+			}
+			// TODO: do we need integrate all the outputs?
+			return jsonindent.NewEncoder(w).Encode(dest)
+		}
 		if err := o.DumpFileMeta(dest, dir, stdout, stderr, w); err != nil {
 			return err
 		}
 	}
+
 	return nil
 }
 
 // DumpFileMeta ...
-func (o Output) DumpFileMeta(dest map[string]map[string]interface{}, dir string, stdout, stderr string, w io.Writer) error {
+func (o Output) DumpFileMeta(dest map[string]interface{}, dir string, stdout, stderr string, w io.Writer) error {
 
 	// This output should not be dumped
 	if o.Binding != nil && o.Binding.LoadContents {