Fix to handle booleans mapping to union type

Author: Soc Sieng

src/convert/unresolved-types-mapper.ts

@@ -105,6 +105,17 @@ export default class UnresolvedTypesMapper {
       }
       // otherwise, do nothing, mapped already contains filtered list
 
+      if (this.containsBoolean(type)) {
+        // replace true | false with boolean
+        const indexTrue = mapped.findIndex(t => t instanceof IntrinsicType && t.name === 'true');
+        const indexFalse = mapped.findIndex(t => t instanceof IntrinsicType && t.name === 'false');
+        const firstIndex = Math.min(indexTrue, indexFalse);
+        const lastIndex = Math.max(indexTrue, indexFalse);
+
+        mapped.splice(firstIndex, 1, new IntrinsicType('boolean'));
+        mapped.splice(lastIndex, 1);
+      }
+
       // get unique list of types from remapped types
       const unique: Type[] = [];
       mapped.forEach(item => {
@@ -143,6 +154,13 @@ export default class UnresolvedTypesMapper {
     return this.isUnmapped(type) ? new UnknownType('unknown') : type;
   }
 
+  private containsBoolean(type: UnionType): boolean {
+    return (
+      !!type.types.find(t => t instanceof IntrinsicType && t.name === 'true')
+      && !!type.types.find(t => t instanceof IntrinsicType && t.name === 'false')
+    );
+  }
+
   private getReflectionsByInstanceType<T extends Reflection>(project: ProjectReflection, func: { new(...args: any[]): T }): T[] {
     return Object.values(project.reflections).filter(r => r instanceof func) as unknown as T[];
   }

tests/test-data/type/expected.d.ts

@@ -7,4 +7,6 @@ declare type StatusTypes = {
    * Failure
    */
   "all-bad": string;
-}
+}
+
+declare type OptionalBoolean = boolean | undefined;

tests/test-data/type/input.ts

@@ -8,3 +8,5 @@ export type StatusTypes = {
    */
   'all-bad': string;
 }
+
+export type OptionalBoolean = boolean | undefined;

tests/test-data/type/optional-expected.d.ts

@@ -0,0 +1,9 @@
+declare interface Optionals {
+  myBool?: boolean;
+  myString?: string;
+  myNumber?: number;
+  otherBool1?: boolean;
+  otherBool2?: boolean;
+  otherBoolUnion1?: boolean | string;
+  otherBoolUnion2?: string | boolean;
+}

tests/test-data/type/optional-input.ts

@@ -0,0 +1,10 @@
+declare interface Optionals {
+  myBool?: boolean;
+  myString?: string;
+  myNumber?: number;
+
+  otherBool1?: true | false;
+  otherBool2?: false | true;
+  otherBoolUnion1?: false | string | true;
+  otherBoolUnion2?: string | true | false | undefined;
+}