update signature of doublemap storage function, add e2e test cases (#957)

* update signature of doublemap storage function

* add test cases

* update doublemap implementation

* update implementation

* remove duplicate test case

* update test cases

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

@@ -232,4 +232,18 @@ describe('createType', () => {
       createType('{"_enum": {"A": null, "B": "u32", "C": null} }', 1).toJSON()
     ).toEqual({ B: 0 });
   });
+
+  it('throw error when create base is a StorageData with null value and isPedantic is true' , () => {
+    const base = createType('StorageData', null);
+    expect(
+      () => createType('DoubleMap<Vec<(BlockNumber,EventIndex)>>', base, true)
+    ).toThrow(/Encoding for input doesn't match output, created 0x00 from 0x/);
+  });
+
+  it('throw error when create base is a StorageData with null value and isPedantic is true' , () => {
+    const base = createType('StorageData', null);
+    expect(
+      () => createType('Vec<(BlockNumber,EventIndex)>', base, true)
+    ).toThrow(/Encoding for input doesn't match output, created 0x00 from 0x/);
+  });
 });

packages/types/src/primitive/StorageKey.ts

@@ -4,7 +4,6 @@
 
 import { assert, isFunction, isString, isU8a } from '@polkadot/util';
 
-import U8a from '../codec/U8a';
 import { StorageFunctionMetadata as MetaV4 } from '../Metadata/v4/Storage';
 import { AnyU8a } from '../types';
 import Bytes from './Bytes';
@@ -70,14 +69,6 @@ export default class StorageKey extends Bytes {
 
       assert(isFunction(fn), 'Expected function input for key construction');
 
-      if (fn.meta && fn.meta.type.isDoubleMap) {
-        return {
-          key: new U8a(fn(...arg)), // skip compact length check in decodeBytes
-          method: fn.method,
-          section: fn.section
-        };
-      }
-
       return {
         key: fn(...arg),
         method: fn.method,