d2lang/d2 · error · Error

response.error.message

Error message

response.error.message

What it means

In the Node worker (worker.js) compile case, d2.compile (WASM) returns a JSON string; a truthy response.error makes the worker throw Error(response.error.message), which is posted back to the main thread and rejects the caller's promise. This is the Node-side counterpart of the browser compile error and surfaces D2 compilation failures.

Source

Thrown at d2js/js/src/worker.js:34

    switch (type) {
      case "init":
        try {
          if (isNode) {
            loadScript(data.wasmExecContent);
          }
          d2 = await initWasm(data.wasm);
          currentPort.postMessage({ type: "ready" });
        } catch (err) {
          currentPort.postMessage({ type: "error", error: err.message });
        }
        break;

      case "compile":
        try {
          const result = await d2.compile(JSON.stringify(data));
          const response = JSON.parse(result);
          if (response.error) throw new Error(response.error.message);
          currentPort.postMessage({ id, type: "result", data: response.data });
        } catch (err) {
          currentPort.postMessage({ id, type: "error", error: err.message });
        }
        break;

      case "render":
        try {
          const result = await d2.render(JSON.stringify(data));
          const response = JSON.parse(result);
          if (response.error) throw new Error(response.error.message);
          const decoded = new TextDecoder().decode(
            Uint8Array.from(atob(response.data), (c) => c.charCodeAt(0))
          );
          currentPort.postMessage({ id, type: "result", data: decoded });
        } catch (err) {
          currentPort.postMessage({ id, type: "error", error: err.message });
        }

View on GitHub (pinned to 0d69dca6f5)

Solutions

1. Fix the diagram source based on the error message (it includes compiler diagnostics)
2. Lint/validate D2 scripts in CI before rendering
3. Check d2.version() for compatibility with any newer syntax used
4. Wrap compile in try/catch and return a meaningful error to the caller

Example fix

// before
await d2.compile('a -> b ->'); // trailing incomplete connection
// after
await d2.compile('a -> b');

if (typeof source !== 'string' || source.trim() === '') {
  throw new TypeError('D2 source must be a non-empty string');
}
const result = await d2.compile(source);

function isCompileInput(input) {
  return typeof input === 'string' ||
    (input !== null && typeof input === 'object' && !Array.isArray(input));
}

try {
  const result = await d2.compile(source);
} catch (err) {
  // err.message contains the D2 compiler diagnostic from the wasm build
  console.error('D2 compile failed (node):', err.message);
  throw new SyntaxError('Invalid D2 script: ' + err.message);
}

When it happens

Trigger: Calling d2.compile() on a D2 instance in Node with a script that fails to compile: syntax errors, invalid references, unknown keywords, or invalid options in the request object.

Common situations: Server-side rendering of user-supplied D2 scripts with syntax errors; CI jobs compiling diagrams checked into a repo with typos; options incompatible with the bundled wasm D2 version.

Related errors

• response.error.message
• response.error.message
• failed to %scompile: %w
• native Markdown SVG does not support HTML element <%s>
• Failed to decompress SourceSansPro-Regular: %v

AI-assisted analysis of d2lang/d2@0d69dca6f5 (2026-08-31). Data as JSON: /api/errors/fc73b369db6f302a. Report an issue: GitHub.