fix: Parse new lines in text/plain as line breaks (BLO-1170)

packages/core/package.json

@@ -119,6 +119,7 @@
     "rehype-parse": "^9.0.1",
     "rehype-remark": "^10.0.1",
     "rehype-stringify": "^10.0.1",
+    "remark-breaks": "^4.0.0",
     "remark-gfm": "^4.0.1",
     "remark-parse": "^11.0.0",
     "remark-rehype": "^11.1.2",

packages/core/src/api/parsers/markdown/parseMarkdown.ts

@@ -1,4 +1,5 @@
 import { Schema } from "prosemirror-model";
+import remarkBreaks from "remark-breaks";
 import remarkGfm from "remark-gfm";
 import remarkParse from "remark-parse";
 import remarkRehype, {
@@ -80,6 +81,7 @@ export function markdownToHTML(markdown: string): string {
   const htmlString = unified()
     .use(remarkParse)
     .use(remarkGfm)
+    .use(remarkBreaks)
     .use(remarkRehype, {
       handlers: {
         ...(remarkRehypeDefaultHandlers as any),

tests/src/unit/core/formatConversion/parse/__snapshots__/markdown/singleNewLines.json

@@ -0,0 +1,22 @@
+[
+  {
+    "children": [],
+    "content": [
+      {
+        "styles": {},
+        "text": "Line 1
+ Line 2
+ Line 3
+ Line 4",
+        "type": "text",
+      },
+    ],
+    "id": "1",
+    "props": {
+      "backgroundColor": "default",
+      "textAlignment": "left",
+      "textColor": "default",
+    },
+    "type": "paragraph",
+  },
+]

tests/src/unit/core/formatConversion/parse/parseTestInstances.ts

@@ -1121,6 +1121,17 @@ Paragraph
 *   Bullet List Item
 
 1.  Numbered List Item
+`,
+    },
+    executeTest: testParseMarkdown,
+  },
+  {
+    testCase: {
+      name: "singleNewLines",
+      content: `Line 1
+Line 2
+Line 3
+Line 4
 `,
     },
     executeTest: testParseMarkdown,