diff --git a/src/language-markdown/embed.js b/src/language-markdown/embed.js
index a9e0d096a..398831601 100644
--- a/src/language-markdown/embed.js
+++ b/src/language-markdown/embed.js
@@ -12,7 +12,8 @@ function embed(path, print, textToDoc, options) {
 
   if (node.type === "code" && node.lang !== null) {
     // only look for the first string so as to support [markdown-preview-enhanced](https://shd101wyy.github.io/markdown-preview-enhanced/#/code-chunk)
-    const lang = node.lang.split(/\s/, 1)[0];
+    const langMatch = node.lang.match(/^[A-Za-z0-9_-]+/);
+    const lang = langMatch ? langMatch[0] : "";
     const parser = getParserName(lang);
     if (parser) {
       const styleUnit = options.__inJsTemplate ? "~" : "`";
diff --git a/tests/multiparser_markdown_js/__snapshots__/jsfmt.spec.js.snap b/tests/multiparser_markdown_js/__snapshots__/jsfmt.spec.js.snap
index d53c85a95..3a3ca97e4 100644
--- a/tests/multiparser_markdown_js/__snapshots__/jsfmt.spec.js.snap
+++ b/tests/multiparser_markdown_js/__snapshots__/jsfmt.spec.js.snap
@@ -41,6 +41,12 @@ console.log(     "hello world"   );
 \`\`\`js {cmd=node .line-numbers}
 console.log(     "hello world"   );
 \`\`\`
+
+## js block with arguments and no space
+
+\`\`\`js{cmd=node .line-numbers}
+console.log(     "hello world"   );
+\`\`\`
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 ## plain js block
 
@@ -54,6 +60,12 @@ console.log("hello world");
 console.log("hello world");
 \`\`\`
 
+## js block with arguments and no space
+
+\`\`\`js{cmd=node .line-numbers}
+console.log("hello world");
+\`\`\`
+
 `;
 
 exports[`trailing-comma.md 1`] = `
diff --git a/tests/multiparser_markdown_js/markdown-preview-enhanced.md b/tests/multiparser_markdown_js/markdown-preview-enhanced.md
index 34f8f3600..9e141ba8b 100644
--- a/tests/multiparser_markdown_js/markdown-preview-enhanced.md
+++ b/tests/multiparser_markdown_js/markdown-preview-enhanced.md
@@ -9,3 +9,9 @@ console.log(     "hello world"   );
 ```js {cmd=node .line-numbers}
 console.log(     "hello world"   );
 ```
+
+## js block with arguments and no space
+
+```js{cmd=node .line-numbers}
+console.log(     "hello world"   );
+```