feat: exactRecurrence to repeat job regardless of the interval of every

REFERENCE.md

@@ -282,7 +282,8 @@ interface RepeatOpts {
   startDate?: Date | string | number; // Start date when the repeat job should start repeating (only with cron).
   endDate?: Date | string | number; // End date when the repeat job should stop repeating.
   limit?: number; // Number of times the job should repeat at max.
-  every?: number; // Repeat every millis (cron setting cannot be used together with this setting.)
+  every?: number; // Repeat every milliseconds within the nearest interval of length "every" (cron setting cannot be used together with this setting.)
+  exactRecurrence?: boolean; // repeat job every n milliseconds regardless the interval of every (only with every.)
   count?: number; // The start value for the repeat iteration count.
 }
 ```

lib/repeatable.js

@@ -192,7 +192,9 @@ module.exports = function(Queue) {
     }
 
     if (opts.every) {
-      return Math.floor(millis / opts.every) * opts.every + opts.every;
+      return opts.exactRecurrence
+        ? millis + opts.every
+        : Math.floor(millis / opts.every) * opts.every + opts.every;
     }
 
     const currentDate =

test/test_repeat.js

@@ -745,4 +745,41 @@ describe('repeat', () => {
       }
     });
   });
+
+  it('should repeat every 2 seconds', function(done) {
+    this.timeout(20000);
+    const _this = this;
+    const date = new Date('2017-02-07 9:24:00');
+    this.clock.tick(date.getTime());
+    const nextTick = 2 * ONE_SECOND + 500;
+
+    queue
+      .add(
+        'repeat',
+        { foo: 'bar' },
+        { repeat: { every: 2000, exactRecurrence: true } }
+      )
+      .then(() => {
+        _this.clock.tick(nextTick);
+      });
+
+    queue.process('repeat', () => {
+      // dummy
+    });
+
+    let prev;
+    let counter = 0;
+    queue.on('completed', job => {
+      _this.clock.tick(nextTick);
+      if (prev) {
+        expect(prev.timestamp).to.be.lt(job.timestamp);
+        expect(job.timestamp - prev.timestamp).to.be.gte(2000);
+      }
+      prev = job;
+      counter++;
+      if (counter == 20) {
+        done();
+      }
+    });
+  });
 });