From 5f96d9fcc56f642c98ee241e54969a2e0d0246b0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Horacio=20Pe=C3=B1a?= <horape@gmail.com>
Date: Fri, 4 Nov 2022 14:59:21 -0300
Subject: [PATCH 1/5] flush: ensure previous flush completion

---
 index.js | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/index.js b/index.js
index 66a8427f..1da08396 100644
--- a/index.js
+++ b/index.js
@@ -52,6 +52,7 @@ class Analytics {
     this.flushInterval = options.flushInterval || 10000
     this.flushed = false
     this.errorHandler = options.errorHandler
+    this.pendingFlush = null
     Object.defineProperty(this, 'enable', {
       configurable: false,
       writable: false,
@@ -236,7 +237,8 @@ class Analytics {
    * @return {Analytics}
    */
 
-  flush (callback) {
+  async flush (callback) {
+    await this.pendingFlush
     callback = callback || noop
 
     if (!this.enable) {
@@ -291,7 +293,8 @@ class Analytics {
       req.timeout = typeof this.timeout === 'string' ? ms(this.timeout) : this.timeout
     }
 
-    return this.axiosInstance.post(`${this.host}${this.path}`, data, req)
+    return (this.pendingFlush = this.axiosInstance
+      .post(`${this.host}${this.path}`, data, req)
       .then(() => {
         done()
         return Promise.resolve(data)
@@ -310,7 +313,7 @@ class Analytics {
 
         done(err)
         throw err
-      })
+      }))
   }
 
   _isErrorRetryable (error) {

From 7428915df9aefe05feb5acde2ae170ddffe56e0d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Horacio=20Pe=C3=B1a?= <horape@gmail.com>
Date: Fri, 4 Nov 2022 15:21:26 -0300
Subject: [PATCH 2/5] allow recovering from failed flushs

---
 index.js | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/index.js b/index.js
index 1da08396..37821a50 100644
--- a/index.js
+++ b/index.js
@@ -237,9 +237,13 @@ class Analytics {
    * @return {Analytics}
    */
 
-  async flush (callback) {
-    await this.pendingFlush
-    callback = callback || noop
+  async flush(callback) {
+    {
+      const pending = this.pendingFlush;
+      this.pendingFlush = null;
+      await pending; // this may throw
+    }
+    callback = callback || noop;
 
     if (!this.enable) {
       setImmediate(callback)

From 51dafbc6c0d6646f2ff432638c9ed9ab0d7a63b3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Horacio=20Pe=C3=B1a?= <horape@gmail.com>
Date: Mon, 7 Nov 2022 14:30:15 -0300
Subject: [PATCH 3/5] standard --fix

---
 index.js | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/index.js b/index.js
index 37821a50..4af5b43c 100644
--- a/index.js
+++ b/index.js
@@ -237,13 +237,13 @@ class Analytics {
    * @return {Analytics}
    */
 
-  async flush(callback) {
+  async flush (callback) {
     {
-      const pending = this.pendingFlush;
-      this.pendingFlush = null;
-      await pending; // this may throw
+      const pending = this.pendingFlush
+      this.pendingFlush = null
+      await pending // this may throw
     }
-    callback = callback || noop;
+    callback = callback || noop
 
     if (!this.enable) {
       setImmediate(callback)

From fda46516cc647d1ee6a7bf22bc21952cd55e4dad Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Horacio=20Pe=C3=B1a?= <horape@gmail.com>
Date: Mon, 7 Nov 2022 18:11:14 -0300
Subject: [PATCH 4/5] fix error handling

---
 index.js | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/index.js b/index.js
index 4af5b43c..95911498 100644
--- a/index.js
+++ b/index.js
@@ -238,10 +238,11 @@ class Analytics {
    */
 
   async flush (callback) {
-    {
-      const pending = this.pendingFlush
+    try {
+      await this.pendingFlush
+    } catch (err) {
       this.pendingFlush = null
-      await pending // this may throw
+      throw err
     }
     callback = callback || noop
 

From edc3ac2a0d5147528dfcfe37fe0e1abab9a69742 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Horacio=20Pe=C3=B1a?= <horape@gmail.com>
Date: Mon, 7 Nov 2022 18:14:55 -0300
Subject: [PATCH 5/5] first check for reasons not to flush and then for pending
 flushes

---
 index.js | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/index.js b/index.js
index 95911498..93842b72 100644
--- a/index.js
+++ b/index.js
@@ -238,12 +238,6 @@ class Analytics {
    */
 
   async flush (callback) {
-    try {
-      await this.pendingFlush
-    } catch (err) {
-      this.pendingFlush = null
-      throw err
-    }
     callback = callback || noop
 
     if (!this.enable) {
@@ -261,6 +255,13 @@ class Analytics {
       return Promise.resolve()
     }
 
+    try {
+      if (this.pendingFlush) { await this.pendingFlush }
+    } catch (err) {
+      this.pendingFlush = null
+      throw err
+    }
+
     const items = this.queue.splice(0, this.flushAt)
     const callbacks = items.map(item => item.callback)
     const messages = items.map(item => item.message)