fix: newline spacing after toc insert

CHANGELOG.md

@@ -1,6 +1,12 @@
 # Changelog
 
 
+## v0.4.2
+
+### Fixed
+- Preserve spacing after TOC on overwrite 
+
+
 ## v0.4.1
 
 ### Fixed

VERSION

@@ -1 +1 @@
-0.4.1
+0.4.2

testdata/basic_toc.md

@@ -11,6 +11,7 @@ An example document with no existing table of contents, but headings of varying
     * [Nest again](#nest-again)
       * [Nest a third time](#nest-a-third-time)
 <!--mdtoc: end-->
+
 ## Heading 1
 
 ### A sub-bullet

testdata/codeblock_toc.md

@@ -6,6 +6,7 @@ An example document with code blocks containing `#` characters to verify these a
 * [Heading 2](#heading-2)
 * [Heading 3](#heading-3)
 <!--mdtoc: end-->
+
 ## Heading 1
 
 ```

testdata/custom_heading_toc.md

@@ -10,6 +10,7 @@ An example document where a custom table of contents heading will be included.
 * [Heading 2](#heading-2)
 * [Heading 3](#heading-3)
 <!--mdtoc: end-->
+
 ## Heading 1
 
 ### A sub-bullet

testdata/ignore_toc.md

@@ -6,6 +6,7 @@ An example document with some headings excluded by using the `<!--mdtoc: ignore-
   * [Another](#another)
 * [Heading 2](#heading-2)
 <!--mdtoc: end-->
+
 ## Heading 1
 
 ### A sub-bullet <!--mdtoc: ignore-->

testdata/repeat_toc.md

@@ -8,6 +8,7 @@ An example document with repeated heading text to verify link generation handles
   * [Testing](#testing-3)
 * [Testing](#testing-4)
 <!--mdtoc: end-->
+
 ## Testing
 ### Testing
 #### Testing

testdata/special_toc.md

@@ -14,6 +14,7 @@ An example document with headings including special/uncommon characters to test
 * [{With braces}](#with-braces)
 * [(With parenthesis)](#with-parenthesis)
 <!--mdtoc: end-->
+
 ## With/Slash
 
 ## With_Underscore

toc.go

@@ -111,8 +111,10 @@ func Insert(b []byte, cfg *Config) ([]byte, error) {
 			inOld = true
 			continue
 		}
-		// end comment, reset flag and skip
+		// end comment, write toc in same location and reset flag
 		if inOld && strings.EqualFold(line, tocEnd) {
+			buf.Write(toc.Bytes())
+			newAdded = true
 			inOld = false
 			continue
 		}
@@ -123,12 +125,11 @@ func Insert(b []byte, cfg *Config) ([]byte, error) {
 
 		// when the first non-title heading is encoutered, insert new toc just before it
 		if !newAdded && headingRegex.FindStringSubmatch(line) != nil {
-			buf.Write(toc.Bytes())
+			buf.Write(append(toc.Bytes(), []byte("\n")...))
 			newAdded = true
 		}
 
-		buf.Write(scanner.Bytes())
-		buf.Write([]byte("\n"))
+		buf.Write(append(scanner.Bytes(), []byte("\n")...))
 	}
 
 	if err := scanner.Err(); err != nil {