Option allows null/undefined as empty (#230)

packages/api/src/index.ts

@@ -199,7 +199,7 @@ export default class Api implements ApiInterface {
         // if we don't have a value, do not fill in the entry, it will be up to the
         // caller to sort this out, either ignoring or having a cache for older values
         result.push(
-          item
+          item && !item.value.isEmpty
             ? createType(type, item.value.value)
             : undefined
         );

packages/types/src/codec/Option.spec.js

@@ -5,25 +5,32 @@
 import Option from './Option';
 import Text from '../Text';
 
-const testDecode = (type, input, expected) =>
+const testDecode = (type, input, expected, testLength = true) =>
   it(`can decode from ${type}`, () => {
     const o = new Option(Text, input);
-    expect(o.isEmpty).toBe(!expected.length)
+
     expect(o.toString()).toBe(expected);
+    expect(o.isEmpty).toBe(testLength && !expected.length);
   });
 
 const testEncode = (to, expected) =>
   it(`can encode ${to}`, () => {
     const e = new Option(Text, 'foo');
+
     expect(e[to]()).toEqual(expected);
   });
 
 describe('Option', () => {
+  it('converts undefined/null to empty', () => {
+    expect(new Option(Text, undefined).isEmpty).toBe(true);
+    expect(new Option(Text, null).isEmpty).toBe(true);
+    expect(new Option(Text, 'test').isEmpty).toBe(false);
+  });
 
   testDecode('string (with)', 'foo', 'foo');
   testDecode('string (without)', undefined, '');
   testDecode('Uint8Array (with)', Uint8Array.from([1, 12, 102, 111, 111]), 'foo');
-  testDecode('Uint8Array (without)', Uint8Array.from([0]), '');
+  testDecode('Uint8Array (without)', Uint8Array.from([0]), '', false);
 
   // testEncode('toHex', '0x010c666f6f'); // FIXME Add this
   testEncode('toString', 'foo');

packages/types/src/codec/Option.ts

@@ -2,6 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
+import isNull from '@polkadot/util/is/null';
 import isU8a from '@polkadot/util/is/u8a';
 import isUndefined from '@polkadot/util/is/undefined';
 
@@ -19,14 +20,19 @@ export default class Option<T> extends Base<Base<T>> {
       Option.decodeOption(Type, value)
     );
 
-    this._isEmpty = isUndefined(value) || value.length <= 1;
+    this._isEmpty = isNull(value) || isUndefined(value);
   }
 
   static decodeOption<O> (Type: { new(value?: any): Base<O> }, value?: any): Base<O> {
     if (isU8a(value)) {
       return new Type(value.subarray(1));
     }
-    return new Type(value);
+
+    return new Type(
+      isNull(value) || isUndefined(value)
+        ? undefined
+        : value
+      );
   }
 
   static with<O> (Type: { new(value?: any): Base<O> }): { new(value?: any): Option<O> } {
@@ -56,7 +62,7 @@ export default class Option<T> extends Base<Base<T>> {
   }
 
   fromJSON (input: any): Option<T> {
-    this._isEmpty = isUndefined(input);
+    this._isEmpty = isNull(input) || isUndefined(input);
 
     if (!this._isEmpty) {
       this.raw.fromJSON(input);