EnumType toJSON to include type & value (#645)

* EnumType toJSON to include type & value

* Update metadata for new EnumType formatting

* PlainType & MapType

packages/types/src/Metadata/v0/Modules.ts

@@ -128,7 +128,7 @@ export class StorageFunctionModifier extends Enum {
   }
 }
 
-export class StorageFunctionType$Map extends Struct {
+export class MapType extends Struct {
   constructor (value?: any) {
     super({
       key: Type,
@@ -151,11 +151,14 @@ export class StorageFunctionType$Map extends Struct {
   }
 }
 
-export class StorageFunctionType extends EnumType<Type | StorageFunctionType$Map> {
+class PlainType extends Type {
+}
+
+export class StorageFunctionType extends EnumType<PlainType | MapType> {
   constructor (value?: any, index?: number) {
     super({
-      Type,
-      StorageFunctionType$Map
+      PlainType,
+      MapType
     }, value, index);
   }
 
@@ -169,15 +172,15 @@ export class StorageFunctionType extends EnumType<Type | StorageFunctionType$Map
   /**
    * @description The value as a mapped value
    */
-  get asMap (): StorageFunctionType$Map {
-    return this.value as StorageFunctionType$Map;
+  get asMap (): MapType {
+    return this.value as MapType;
   }
 
   /**
    * @description The value as a [[Type]] value
    */
-  get asType (): Type {
-    return this.value as Type;
+  get asType (): PlainType {
+    return this.value as PlainType;
   }
 
   /**

packages/types/src/codec/EnumType.spec.ts

@@ -62,6 +62,23 @@ describe('Struct', () => {
     ).toEqual('Null');
   });
 
+  it('stringifies with custom types', () => {
+    class A extends Null { }
+    class B extends Null { }
+    class C extends Null { }
+    class Test extends EnumType<A | B | C> {
+      constructor (value?: string, index?: number) {
+        super({
+          a: A,
+          b: B,
+          c: C
+        }, value, index);
+      }
+    }
+
+    expect(new Test().toJSON()).toEqual({ a: null });
+  });
+
   // We are currently not using this approach, none of the types in Substrate currently
   // have any overrides. Insteda of trying to support it (just-in-case), rather have it
   // removed to simplyfy the code - it can be pulled-back if needed

packages/types/src/codec/EnumType.ts

@@ -161,7 +161,9 @@ export default class EnumType<T> extends Base<Codec> implements Codec {
    * @description Converts the Object to JSON, typically used for RPC transfers
    */
   toJSON (): any {
-    return this.raw;
+    return {
+      [this.type]: this.raw.toJSON()
+    };
   }
 
   /**