add tests and improve newline behaviour

platforms/web/lib/conversion.test.ts

@@ -80,6 +80,30 @@ describe('Rich text <=> plain text', () => {
 
         expect(convertedRichText).toBe(expectedRichText);
     });
+
+    it('converts code spans from plain => rich', async () => {
+        const plainText = '```I am a code span```';
+        const convertedRichText = await plainToRich(plainText, false);
+        const expectedRichText = '<code>I am a code span</code>';
+
+        expect(convertedRichText).toBe(expectedRichText);
+    });
+
+    it('converts code blocks from plain => rich with newline separation', async () => {
+        const plainText = '```\nI am a code block\n```';
+        const convertedRichText = await plainToRich(plainText, false);
+        const expectedRichText = '<pre><code>I am a code block</code></pre>';
+
+        expect(convertedRichText).toBe(expectedRichText);
+    });
+
+    it('converts code blocks from plain => rich with div separation', async () => {
+        const plainText = '```<div>I codeblock</div><div>```</div>';
+        const convertedRichText = await plainToRich(plainText, false);
+        const expectedRichText = '<pre><code>I codeblock</code></pre>';
+
+        expect(convertedRichText).toBe(expectedRichText);
+    });
 });
 
 describe('markdownToPlain', () => {
@@ -92,11 +116,9 @@ describe('markdownToPlain', () => {
     });
 
     it('converts multiple linebreak for markdown => plain', () => {
-        // nb for correct display, there will be one \n more
-        // than \\\n at the end
         const markdown = 'multiple\\\nline\\\n\\\nbreaks\\\n\\\n\\\n';
         const convertedPlainText = markdownToPlain(markdown);
-        const expectedPlainText = 'multiple\nline\n\nbreaks\n\n\n\n';
+        const expectedPlainText = 'multiple\nline\n\nbreaks\n\n';
 
         expect(convertedPlainText).toBe(expectedPlainText);
     });

platforms/web/lib/conversion.ts

@@ -24,14 +24,14 @@ import { initOnce } from './useComposerModel.js';
 const NEWLINE_CHAR = '\n';
 
 // In plain text, markdown newlines (displays '\' character followed by
-// a newline character) will be represented as \n for display as the
-// display box can not interpret markdown.
-// We also may need to manually add a \n to account for trailing newlines.
+// a newline character) will be represented as \n for setting in the composer.
+// If we have a trailing newline character, we trim it off so that the cursor
+// will always be at the last character of the string, not on a new line in the
+// composer.
 export const markdownToPlain = (markdown: string) => {
     let plainText = markdown;
     if (plainText.endsWith(NEWLINE_CHAR)) {
-        // for cursor positioning we need to manually add another linebreak
-        plainText = `${plainText}${NEWLINE_CHAR}`;
+        plainText = plainText.slice(0, -1);
     }
     return plainText.replaceAll(/\\/g, '');
 };