Fix #2720

src/mfm/html.ts

@@ -82,9 +82,13 @@ const handlers: { [key: string]: (window: any, token: any, mentionedRemoteUsers:
 
 	text({ document }, { content }) {
 		const nodes = (content as string).split('\n').map(x => document.createTextNode(x));
-		for (const x of intersperse(document.createElement('br'), nodes)) {
+		for (const x of intersperse('br', nodes)) {
+			if (x === 'br') {
+				document.body.appendChild(document.createElement('br'));
+			} else {
 				document.body.appendChild(x);
 			}
+		}
 	},
 
 	url({ document }, { url }) {

test/mfm.ts

@@ -1,6 +1,7 @@
 import * as assert from 'assert';
 
 import analyze from '../src/mfm/parse';
+import toHtml from '../src/mfm/html';
 import syntaxhighlighter from '../src/mfm/parse/core/syntax-highlighter';
 
 describe('Text', () => {
@@ -170,4 +171,12 @@ describe('Text', () => {
 			assert.equal(html, '<span class="symbol">/</span>');
 		});
 	});
+
+	describe('toHtml', () => {
+		it('br', () => {
+			const input = 'foo\nbar\nbaz';
+			const output = '<p>foo<br>bar<br>baz</p>';
+			assert.equal(toHtml(analyze(input)), output);
+		});
+	});
 });