Merge pull request #22 from electron/return-type-values

Add enum support to typify.  Fixes #20

Author: zeke

lib/utils.js

@@ -39,6 +39,9 @@ const typify = (type) => {
 
   if (typeof type === 'object') {
     let newType = type.typeName || type.type || 'any'
+    if (newType.toLowerCase() === 'string' && type.possibleValues) {
+      newType = `(${type.possibleValues.map(value => `'${value.value}'`).join(' | ')})`
+    }
     if (type.collection) {
       type = newType + '[]'
     } else {