fix(transform): check final transforms return type

docs/controller/echo-controller.yml

@@ -0,0 +1,16 @@
+metadata:
+  kind: echo-controller
+  name: test-echo-controller
+data:
+  defaultTarget:
+    kind: slack-listener
+    name: slack-isolex
+
+  filters: []
+  transforms:
+    - metadata:
+        kind: template-transform
+        name: test-echo-template
+      data:
+        templates:
+          body: "{{ json this }}"

docs/isolex.yml

@@ -20,6 +20,7 @@ data:
     - !include ../docs/controller/command-controller.yml
     - !include ../docs/controller/completion-controller.yml
     - !include ../docs/controller/dice-controller.yml
+    - !include ../docs/controller/echo-controller.yml
     - !include ../docs/controller/github/pr-controller.yml
     - !include ../docs/controller/gitlab/ci-controller.yml
     - !include ../docs/controller/gitlab/endpoint/push-controller.yml

src/controller/BaseController.ts

@@ -1,4 +1,4 @@
-import { isNil, isString } from 'lodash';
+import { isNil } from 'lodash';
 import { Inject, MissingValueError } from 'noicejs';
 
 import { Controller, ControllerData, getHandlerOptions, HandlerOptions } from '.';
@@ -12,7 +12,7 @@ import { Listener } from '../listener';
 import { Locale, TranslateOptions } from '../locale';
 import { ServiceModule } from '../module/ServiceModule';
 import { ServiceDefinition } from '../Service';
-import { applyTransforms, Transform, TransformData } from '../transform';
+import { applyTransforms, extractBody, Transform, TransformData } from '../transform';
 import { doesExist, mustCoalesce, mustExist } from '../utils';
 import { TYPE_JSON, TYPE_TEXT } from '../utils/Mime';
 import { getMethods } from '../utils/Reflect';
@@ -151,12 +151,8 @@ export abstract class BaseController<TData extends ControllerData> extends BotSe
     const result = await applyTransforms(this.transforms, cmd, TYPE_JSON, data);
     this.logger.debug({ result }, 'transformed json results');
 
-    const [body] = result.body;
-    if (isString(body)) {
-      return this.reply(mustCoalesce(ctx, cmd.context), body);
-    } else {
-      this.logger.error({ body }, 'final transform did not return a string');
-    }
+    const body = extractBody(result);
+    return this.reply(mustCoalesce(ctx, cmd.context), body);
   }
 
   protected async errorReply(ctx: Context, errCode: ErrorReplyType, msg?: string): Promise<void> {

src/generator/MessageGenerator.ts

@@ -1,13 +1,10 @@
-import { isString } from 'lodash';
-import { BaseError } from 'noicejs';
-
 import { GeneratorData } from '.';
 import { Context } from '../entity/Context';
 import { Message, MessageEntityOptions } from '../entity/Message';
 import { Tick } from '../entity/Tick';
 import { NotInitializedError } from '../error/NotInitializedError';
 import { ServiceDefinition } from '../Service';
-import { applyTransforms, Transform, TransformData } from '../transform';
+import { applyTransforms, extractBody, Transform, TransformData } from '../transform';
 import { BaseGenerator, BaseIntervalOptions } from './BaseGenerator';
 
 export interface MessageGeneratorData extends GeneratorData {
@@ -54,17 +51,15 @@ export class MessageGenerator extends BaseGenerator<MessageGeneratorData> {
       context,
     });
 
-    const body = await applyTransforms(this.transforms, initial, this.data.defaultMessage.type, {
+    const result = await applyTransforms(this.transforms, initial, this.data.defaultMessage.type, {
       last,
       next,
     });
-    if (!isString(body.body)) {
-      throw new BaseError('final transform did not return a string');
-    }
 
+    const body = extractBody(result);
     await this.bot.sendMessage(new Message({
       ...initial,
-      body: body.body,
+      body,
     }));
     return 0;
   }

src/transform/TemplateTransform.ts

@@ -39,7 +39,11 @@ export class TemplateTransform extends BaseTransform<TemplateTransformData> impl
       this.logger.debug({ key, scope }, 'rendering template with scope');
       const result = template.render(scope);
       this.logger.debug({ key, result }, 'rendered template with scope');
-      out.set(key, result);
+      if (Array.isArray(result)) {
+        out.set(key, result);
+      } else {
+        out.set(key, [result]);
+      }
     }
     return makeDict(out);
   }

src/transform/index.ts

@@ -1,3 +1,6 @@
+import { isString } from 'lodash';
+import { BaseError } from 'noicejs';
+
 import { BotServiceData } from '../BotService';
 import { FilterData, FilterValue } from '../filter';
 import { Service, ServiceDefinition } from '../Service';
@@ -41,3 +44,16 @@ export async function applyTransforms(
 
   return makeDict(output);
 }
+
+export function extractBody(data: TransformOutput): string {
+  if (!Array.isArray(data.body)) {
+    throw new BaseError('final transform did not return body array');
+  }
+
+  const [body] = data.body;
+  if (!isString(body)) {
+    throw new BaseError('final transform did not return a string');
+  }
+
+  return body;
+}

test/transform/TestTemplateTransform.ts

@@ -45,6 +45,8 @@ describeLeaks('template transform', async () => {
       verb: CommandVerb.Get,
     }), TYPE_JSON, data);
 
-    expect(output).to.deep.equal(templates);
+    expect(output).to.deep.equal({
+      body: [templates.body],
+    });
   });
 });