facebook/docusaurus · error · Error

MDX compilation failed for file ${logger.path(filePath)} Cau

Error message

MDX compilation failed for file ${logger.path(filePath)}
Cause: ${error.message}
Details:
${errorDetails}

What it means

Thrown by compileToJSX() in @docusaurus/mdx-loader when the MDX/remark processor fails to compile a markdown/MDX file. It wraps the underlying error with the file path, message, and (for MDX errors) the JSON-serialized error attributes plus the stack trace, attaching the original as `cause`. This is the error you see in webpack stats when an MDX file is malformed.

Source

Thrown at packages/docusaurus-mdx-loader/src/utils.ts:126

    return await processor.process({
      content: preprocessedFileContent,
      filePath,
      frontMatter,
      compilerName,
    });
  } catch (errorUnknown) {
    const error = errorUnknown as Error;

    // MDX can emit errors that have useful extra attributes
    const errorJSON = JSON.stringify(error, null, 2);
    const errorDetails =
      errorJSON === '{}'
        ? // regular JS error case: print stacktrace
          (error.stack ?? 'N/A')
        : // MDX error: print extra attributes + stacktrace
          `${errorJSON}\n${error.stack}`;

    throw new Error(
      `MDX compilation failed for file ${logger.path(filePath)}\nCause: ${
        error.message
      }\nDetails:\n${errorDetails}`,
      // TODO error cause doesn't seem to be used by Webpack stats.errors :s
      {cause: errorUnknown},
    );
  }
}

View on GitHub (pinned to 3f483e80e3)

Solutions

Read the full error: the 'Cause:' line gives the MDX message, 'Details:' gives line/column and the offending source.
Open the named filePath at the reported line and fix the JSX/markdown.
If a custom remark/retext plugin is involved, disable it temporarily to isolate the cause.
After fixing, rebuild; MDX errors are deterministic per file.

Example fix

<!-- before -->
<MyComp prop="x">
# Title
<!-- after -->
<MyComp prop="x">
  # Title
</MyComp>

Defensive patterns

Strategy: try-catch

Validate before calling

import {compile} from '@mdx-js/mdx';
// pre-compile MDX files in a lint step:
async function mdxLints(file: string) {
  try { await compile(await import('node:fs/promises').then(f => f.readFile(file, 'utf8'))); }
  catch (e) { console.warn(`MDX lint failed: ${file}: ${(e as Error).message}`); }
}

Try / catch

try {
  await compileToJSX({filePath, fileContent, frontMatter, options, compilerName});
} catch (err) {
  // err.cause is the original MDX error with position
  throw new Error(`Build aborted: MDX error in ${filePath}`, {cause: err});
}

Prevention

Lint JSX inside MDX in your editor (MDX language server).
Keep custom remark/retext plugins version-aligned with @docusaurus/mdx-loader.
Run the build locally before pushing; MDX errors are deterministic.

When it happens

Trigger: An MDX file with invalid JSX (<div> without closing tag), a remark/retext plugin throwing, unsupported MDX syntax, importing a nonexistent component, or invalid front matter that fails validateMDXFrontMatter. Any uncaught error inside processor.process() lands here.

Common situations: Writing JSX inside MDX with mismatched tags; referencing an undefined component via MDX provider; a custom remark plugin incompatible with the installed MDX version; malformed code fences; a typo in an mdx front-matter value.

Related errors

AI-assisted analysis of facebook/docusaurus@3f483e80e3 (2026-08-12). Data as JSON: /api/errors/58ebe0df1d684fa5. Report an issue: GitHub.