supports union type & null type

CHANGELOG.md

@@ -1,3 +1,10 @@
+## 1.8.0
+
+- supports union types
+- supports null type
+
+So we can express the type `string | null`
+
 ## 1.7.3
 
 - export `Int` branded type

README.md

@@ -51,16 +51,17 @@ Since its main purpose is for JSON validation, only a subset of interface syntax
 2. Other acceptable interfaces
 3. Classes
 4. Literal types (i.e. `interface Address { pos: { lat: number; lng: number; } }`, here `Address.pos` is a literal type)
-5. Array type of 1-4
+5. Union types
+6. null type
+7. Array type of 1-5
 
 Also
 
 1. The fields in the interface CAN be marked as optional.
 2. Generic types are NOT supported.
-3. Union types are NOT supported yet (PR, feature request welcomed if you really need this to work with a bad-designed API)
-4. `null`, `any`, `unknown` are illegal.
-5. Recursive types are NOT supported.
-6. intersection types are NOT supported YET. (it's useful to implement custom validations)
+3. `any`, `unknown` are illegal.
+4. Recursive types are NOT supported.
+5. intersection types are NOT supported YET.
 
 ### You need declare schemas in topological order
 

build.sh

@@ -2,12 +2,13 @@
 
 rm -rf lib/
 
-cp ./node_modules/ts-transformer-interface/transformer.ts ./transform-interface.ts
-cp ./node_modules/ts-transformer-interface/runtime-schema.ts ./runtime-schema.ts
-cp ./node_modules/ts-transformer-decoder-cast/transformer.ts ./transform-request.ts
+cp ./node_modules/ts-transformer-interface/transformer.d.ts ./transform-interface.d.ts
+cp ./node_modules/ts-transformer-interface/transformer.js ./transform-interface.js
+
+cp ./node_modules/ts-transformer-interface/runtime-schema.d.ts ./runtime-schema.d.ts
+cp ./node_modules/ts-transformer-interface/runtime-schema.js ./runtime-schema.js
 
-cat runtime-schema.ts | sed 's/index.d/index/' > replaced
-mv replaced runtime-schema.ts
+cp ./node_modules/ts-transformer-decoder-cast/transformer.ts ./transform-request.ts
 
 tsc
 npx pretty-quick

index.ts

@@ -31,6 +31,7 @@ const TypeC: t.Type<runtime.Type> = t.recursion('TypeC', () =>
     ParameterizedTypeC,
     GenericTypeC,
     LiteralTypeC,
+    UnionTypeC,
   ]),
 );
 
@@ -52,6 +53,10 @@ const ParameterizedTypeC: t.Type<runtime.ParameterizedType> = t.type({
   typeArgumentType: TypeC,
 });
 
+const UnionTypeC: t.Type<runtime.UnionType> = t.type({
+  union: t.array(TypeC),
+});
+
 const PropertyC: t.Type<runtime.Property> = t.type({
   name: t.string,
   type: TypeC,
@@ -326,13 +331,18 @@ export class Decoder implements ICaster {
     if (LiteralTypeC.is(type)) {
       return t.type(this.buildCasters(type.props));
     }
+    if (UnionTypeC.is(type)) {
+      return type.union.map(t => this.buildTypeCaster(t)).reduce((t1, t2) => t.union([t1, t2]));
+    }
     switch (type) {
       case 'string':
         return t.string;
       case 'number':
         return t.number;
       case 'boolean':
         return t.boolean;
+      case 'null':
+        return t.null;
       default:
         throw new Error(`illegal decoder type ${JSON.stringify(type)}`);
     }

test/sample.ts

@@ -458,3 +458,37 @@ const decoded188 = dec.decode(
 if (JSON.stringify(good188) !== JSON.stringify(decoded188)) {
   throw new Error('nested Array NOT WORKING!!!');
 }
+
+// union type
+console.log('union types');
+interface House {
+  owner: Customer | null;
+}
+dec.register(schema<House>());
+
+const house = {
+  owner: {
+    firstName: 'Yang',
+    lastName: 'Liu',
+  },
+};
+
+const decodedHouse = dec.decode('House', house, e => {
+  throw e;
+});
+if (!decodedHouse) {
+  throw new Error('Union type NOT WORKING!');
+} else {
+  console.log(decodedHouse);
+}
+
+const house2 = { owner: null };
+const decodedHouse2 = dec.decode('House', house2, e => {
+  throw e;
+});
+if (!decodedHouse2) {
+  throw new Error('Union type (with null) NOT WORKING!');
+} else {
+  console.log(decodedHouse2);
+}
+console.log('-'.repeat(40));