fix the <img> conversion, it wouldn't convert an svg link

Author: maelvls

README.md

@@ -187,9 +187,24 @@ I use the `hudevto preview` command because I do some transformations and I need
   ```text
   ![My image](/you-should-write-comments/cover-you-should-write-comments.png)
               <------ basePostURL ------>
-              (basePostURL includes the trailing /)
+              (basePostURL includes the leading / and trailing /)
   ```
 
+  Since you can also embed `<img>` tags in markdown, these are also converted. For example,
+
+  ```markdown
+  <img alt="Super example" src="dnat-google-vpc-how-comes-back.svg" width="80%"/>
+  ```
+
+  becomes:
+
+  ```markdown
+  <img alt="Super example" src="/you-should-write-comments/dnat-google-vpc-how-comes-back.svg" width="80%"/>
+  ```
+
+  Only the following image extensions are converted: png, PNG, jpeg, JPG, jpg,
+  gif, GIF, svg, SVG.
+
 - The GitHub-style anchor IDs are converted to Devto anchor IDs. This is because
   GitHub-style anchor IDs, which is what Hugo produces, are different from the
   ones produced by Devto. For example, take the following Markdown:

main.go

@@ -869,7 +869,7 @@ func convertHugoToLiquid(in string) string {
 //
 //	![My image](/you-should-write-comments/cover-you-should-write-comments.png)
 //	            <------ basePostURL ------>
-//	           (note that basePostURL includes the trailing '/')
+//	           (basePostURL already includes the leading / and trailing /)
 //
 // Note: (?s) means multiline, (?U) means non-greedy.
 var mdImg = regexp.MustCompile(`(?sU)\!\[([^\]]*)\]\((\S*)\)`)
@@ -878,8 +878,10 @@ func addPostURLInImages(in string, basePostURL string) string {
 	return mdImg.ReplaceAllString(in, "![$1]("+basePostURL+"$2)")
 }
 
+// Same, but for HTML <img> tags embedded in Markdown.
+//
 // (?s) means multiline, (?U) means non-greedy.
-var htmlImg = regexp.MustCompile(`(?sU)src="([^"]*(png|PNG|jpeg|JPG|jpg|gif|GIF))"`)
+var htmlImg = regexp.MustCompile(`(?sU)src="([^"]*(png|PNG|jpeg|JPG|jpg|gif|GIF|svg|SVG))"`)
 
 func addPostURLInHTMLImages(in string, basePostURL string) string {
 	return htmlImg.ReplaceAllString(in, `src="`+basePostURL+`$1"`)

main_test.go

@@ -32,3 +32,19 @@ func Test_convertAnchorIDs(t *testing.T) {
 		})
 	}
 }
+
+func Test_addPostURLInHTMLImages(t *testing.T) {
+	tests := []struct {
+		given, expect string
+	}{
+		{
+			`<img alt="Super example" src="dnat-google-vpc-how-comes-back.svg" width="80%"/>`,
+			`<img alt="Super example" src="/you-should-write-comments/dnat-google-vpc-how-comes-back.svg" width="80%"/>`,
+		},
+	}
+	for i, tt := range tests {
+		t.Run(strconv.Itoa(i), func(t *testing.T) {
+			assert.Equal(t, tt.expect, addPostURLInHTMLImages(tt.given, "/you-should-write-comments/"))
+		})
+	}
+}