add guards to specSelectors

src/core/plugins/spec/selectors.js

@@ -278,6 +278,7 @@ export const hasHost = createSelector(
 
 // Get the parameter values, that the user filled out
 export function parameterValues(state, pathMethod, isXml) {
+  pathMethod = pathMethod || []
   let params = spec(state).getIn(["paths", ...pathMethod, "parameters"], fromJS([]))
   return params.reduce( (hash, p) => {
     let value = isXml && p.get("in") === "body" ? p.get("value_xml") : p.get("value")
@@ -301,6 +302,7 @@ export function parametersIncludeType(parameters, typeValue="") {
 
 // Get the consumes/produces value that the user selected
 export function contentTypeValues(state, pathMethod) {
+  pathMethod = pathMethod || []
   let op = spec(state).getIn(["paths", ...pathMethod], fromJS({}))
   const parameters = op.get("parameters") || new List()
 
@@ -319,6 +321,7 @@ export function contentTypeValues(state, pathMethod) {
 
 // Get the consumes/produces by path
 export function operationConsumes(state, pathMethod) {
+  pathMethod = pathMethod || []
   return spec(state).getIn(["paths", ...pathMethod, "consumes"], fromJS({}))
 }
 
@@ -335,6 +338,7 @@ export const canExecuteScheme = ( state, path, method ) => {
 }
 
 export const validateBeforeExecute = ( state, pathMethod ) => {
+  pathMethod = pathMethod || []
   let params = spec(state).getIn(["paths", ...pathMethod, "parameters"], fromJS([]))
   let isValid = true