emit on worker completion

with test

src/helpers/constants.js

@@ -17,6 +17,7 @@ export const events = {
   EVENT_JOB_CREATED: 'job:created',
   EVENT_JOB_ERROR: 'job:error',
   EVENT_WORKER_ERROR: 'worker:error',
+  EVENT_WORKER_COMPLETE: 'worker:job complete',
   EVENT_WORKER_JOB_CLAIM_ERROR: 'worker:claim job error',
   EVENT_WORKER_JOB_SEARCH_ERROR: 'worker:pending jobs error',
   EVENT_WORKER_JOB_UPDATE_ERROR: 'worker:update job error',

src/worker.js

@@ -195,6 +195,7 @@ export default class Job extends events.EventEmitter {
         version: job._version,
         body: { doc }
       })
+      .then(() => this.emit(constants.EVENT_WORKER_COMPLETE, Object.assign(emitJob, { output: docOutput })))
       .catch((err) => {
         if (err.statusCode === 409) return false;
         this.debug(`Failure saving job output ${job._id}`, err);

test/src/worker.js

@@ -564,6 +564,27 @@ describe('Worker class', function () {
           expect(completedTimestamp).to.be.greaterThan(startTime);
         });
       });
+
+      it('should emit completion event', function (done) {
+        const worker = new Worker(mockQueue, 'test', noop);
+
+        worker.once(constants.EVENT_WORKER_COMPLETE, (workerJob) => {
+          try {
+            expect(workerJob).to.have.property('id');
+            expect(workerJob).to.have.property('index');
+            expect(workerJob).to.have.property('type');
+            expect(workerJob).to.have.property('output');
+            expect(workerJob.output).to.have.property('content');
+            expect(workerJob.output).to.have.property('content_type');
+            expect(workerJob).to.not.have.property('_source');
+            done();
+          } catch (e) {
+            done(e);
+          }
+        });
+
+        worker._performJob(job);
+      });
     });
 
     describe('worker failure', function () {