Handle falsy option values (#188)

Author: jsdt

packages/sdk/src/algebraic_type.ts

@@ -62,7 +62,7 @@ export class SumType {
       this.variants[0].name === 'some' &&
       this.variants[1].name === 'none'
     ) {
-      if (value) {
+      if (value !== null && value !== undefined) {
         writer.writeByte(0);
         this.variants[0].algebraicType.serialize(writer, value);
       } else {

packages/sdk/tests/algebraic_value.test.ts

@@ -7,6 +7,7 @@ import {
   SumValue,
 } from '../src/algebraic_value';
 import BinaryReader from '../src/binary_reader';
+import BinaryWriter from '../src/binary_writer';
 
 describe('AlgebraicValue', () => {
   test('when created with a ProductValue it assigns the product property', () => {
@@ -27,6 +28,52 @@ describe('AlgebraicValue', () => {
     expect(av.asString()).toBe('foo');
   });
 
+  test('options handle falsy strings', () => {
+    let stringOptionType = AlgebraicType.createOptionType(
+      AlgebraicType.createStringType()
+    );
+    let writer = new BinaryWriter(1024);
+    stringOptionType.serialize(writer, '');
+    let parsed = stringOptionType.deserialize(
+      new BinaryReader(writer.getBuffer())
+    );
+    // Make sure we don't turn this into undefined.
+    expect(parsed).toEqual('');
+
+    writer = new BinaryWriter(1024);
+    stringOptionType.serialize(writer, null);
+    parsed = stringOptionType.deserialize(new BinaryReader(writer.getBuffer()));
+    expect(parsed).toEqual(undefined);
+
+    writer = new BinaryWriter(1024);
+    stringOptionType.serialize(writer, undefined);
+    parsed = stringOptionType.deserialize(new BinaryReader(writer.getBuffer()));
+    expect(parsed).toEqual(undefined);
+  });
+
+  test('options handle falsy numbers', () => {
+    let stringOptionType = AlgebraicType.createOptionType(
+      AlgebraicType.createU32Type()
+    );
+    let writer = new BinaryWriter(1024);
+    stringOptionType.serialize(writer, 0);
+    let parsed = stringOptionType.deserialize(
+      new BinaryReader(writer.getBuffer())
+    );
+    // Make sure we don't turn this into undefined.
+    expect(parsed).toEqual(0);
+
+    writer = new BinaryWriter(1024);
+    stringOptionType.serialize(writer, null);
+    parsed = stringOptionType.deserialize(new BinaryReader(writer.getBuffer()));
+    expect(parsed).toEqual(undefined);
+
+    writer = new BinaryWriter(1024);
+    stringOptionType.serialize(writer, undefined);
+    parsed = stringOptionType.deserialize(new BinaryReader(writer.getBuffer()));
+    expect(parsed).toEqual(undefined);
+  });
+
   test('when created with a AlgebraicValue(AlgebraicValue[]) it can be requested as an array', () => {
     let array: AlgebraicValue[] = [new AlgebraicValue(1)];
     let av = new AlgebraicValue(array);