From a826a9c3e08791dc24f368803145fdd77e75e97d Mon Sep 17 00:00:00 2001
From: eliot-akira <me@eliotakira.com>
Date: Tue, 5 Oct 2021 12:11:36 +0200
Subject: [PATCH] Align behavior of treatRawData and treatRawStream in handling
 last blank line; On error, result is null

---
 lib/persistence.js       | 15 ++++++++++-----
 test/persistence.test.js |  2 +-
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/lib/persistence.js b/lib/persistence.js
index 81a9e71..4839693 100755
--- a/lib/persistence.js
+++ b/lib/persistence.js
@@ -158,6 +158,8 @@ class Persistence {
     const dataById = {}
     const tdata = []
     const indexes = {}
+
+    // Last line of every data file is usually blank so not really corrupt
     let corruptItems = -1
 
     for (const datum of data) {
@@ -192,9 +194,11 @@ class Persistence {
     const dataById = {}
     const tdata = []
     const indexes = {}
-    let corruptItems = 0
 
-    const lineStream = byline(rawStream)
+    // Last line of every data file is usually blank so not really corrupt
+    let corruptItems = -1
+
+    const lineStream = byline(rawStream, { keepEmptyLines: true })
     let length = 0
 
     lineStream.on('data', (line) => {
@@ -214,16 +218,17 @@ class Persistence {
 
     lineStream.on('end', () => {
       // A bit lenient on corruption
-      let err = null
       if (length > 0 && corruptItems / length > this.corruptAlertThreshold) {
-        err = new Error(`More than ${Math.floor(100 * this.corruptAlertThreshold)}% of the data file is corrupt, the wrong beforeDeserialization hook may be used. Cautiously refusing to start NeDB to prevent dataloss`)
+        const err = new Error(`More than ${Math.floor(100 * this.corruptAlertThreshold)}% of the data file is corrupt, the wrong beforeDeserialization hook may be used. Cautiously refusing to start NeDB to prevent dataloss`)
+        cb(err, null)
+        return
       }
 
       Object.keys(dataById).forEach(function (k) {
         tdata.push(dataById[k])
       })
 
-      cb(err, { data: tdata, indexes: indexes })
+      cb(null, { data: tdata, indexes: indexes })
     })
 
     lineStream.on('error', function (err) {
diff --git a/test/persistence.test.js b/test/persistence.test.js
index ba614c7..ec35f02 100755
--- a/test/persistence.test.js
+++ b/test/persistence.test.js
@@ -102,7 +102,7 @@ describe('Persistence', function () {
     stream.push(null)
 
     d.persistence.treatRawStream(stream, function (err, result) {
-      assert.isNotNull(err)
+      assert.isNull(err)
       const treatedData = result.data
       treatedData.sort(function (a, b) { return a._id - b._id })
       treatedData.length.should.equal(2)