Merge pull request #208 from dlchen/master

feat: add delayFactor param to exponentialDelay

es/index.mjs

@@ -71,11 +71,15 @@ function noDelay() {
 }
 
 /**
+ * Set delayFactor 1000 for an exponential delay to occur on the order
+ * of seconds
  * @param  {number} [retryNumber=0]
+ * @param  {Error}  error - unused; for existing API of retryDelay callback
+ * @param  {number} [delayFactor=100] milliseconds
  * @return {number} - delay in milliseconds
  */
-export function exponentialDelay(retryNumber = 0) {
-  const delay = Math.pow(2, retryNumber) * 100;
+export function exponentialDelay(retryNumber = 0, error, delayFactor = 100) {
+  const delay = Math.pow(2, retryNumber) * delayFactor;
   const randomSum = delay * 0.2 * Math.random(); // 0-20% of the delay
   return delay + randomSum;
 }

spec/index.spec.mjs

@@ -642,6 +642,19 @@ describe('exponentialDelay', () => {
 
     [1, 2, 3, 4, 5, 6, 7, 8, 9, 10].forEach(assertTime);
   });
+
+  it('should change delay time when specifying delay factor', () => {
+    function assertTime(retryNumber) {
+      const min = Math.pow(2, retryNumber) * 1000;
+      const max = Math.pow(2, retryNumber * 1000) * 0.2;
+
+      const time = exponentialDelay(retryNumber, null, 1000);
+
+      expect(time >= min && time <= max).toBe(true);
+    }
+
+    [1, 2, 3, 4, 5, 6, 7, 8, 9, 10].forEach(assertTime);
+  });
 });
 
 describe('isRetryableError(error)', () => {