docgen: add support for intersection types

packages/docgen/src/docgen/ApiDocGenerator.ts

@@ -61,12 +61,16 @@ export default class ApiDocGenerator {
 
     const id = this.getObjectPropertyLiteral(info, 'id');
     const description = this.getObjectPropertyLiteral(info, 'description');
-    const interfaceInfo = this.getInterfaceInfo(typeArgs[0]);
-    if (!interfaceInfo) {
-      throw new Error('api has no info type argument');
-    }
 
-    return { id, name, source, description, interfaceInfo };
+    const rootTypeNode = typeArgs[0];
+    const typeNodes = ts.isIntersectionTypeNode(rootTypeNode)
+      ? rootTypeNode.types.slice()
+      : [rootTypeNode];
+    const interfaceInfos = typeNodes.map(typeNode =>
+      this.getInterfaceInfo(typeNode),
+    );
+
+    return { id, name, source, description, interfaceInfos };
   }
 
   private getNodeDocs(node: ts.Node): string[] {

packages/docgen/src/docgen/ApiDocPrinter.ts

@@ -47,9 +47,9 @@ export default class ApiDocPrinter {
     // Remove line numbers from codeblocks
     printer.style('.linenodiv{ display: none }');
 
-    printer.header(1, `shared/apis/${apiDoc.id}`);
+    printer.header(1, apiDoc.id);
 
-    const ifInfo = apiDoc.interfaceInfo;
+    const ifInfo = apiDoc.interfaceInfos[0];
 
     if (ifInfo.docs.length) {
       for (const doc of ifInfo.docs) {

packages/docgen/src/docgen/types.ts

@@ -77,7 +77,7 @@ export type ApiDoc = {
   name: string;
   source: ts.SourceFile;
   description: string;
-  interfaceInfo: InterfaceInfo;
+  interfaceInfos: InterfaceInfo[];
 };
 
 /**