Function parseDataLine

packages/fetch/src/stream.ts:76–109

(line: string)

// Export for testing purposes
export function parseDataLine(line: string): any {
  const json = line.startsWith("data: ")
    ? line.slice("data: ".length)
    : line.slice("data:".length);

  try {
    const data = JSON.parse(json);
    if (data.error) {
      if (
        data.error &&
        typeof data.error === "object" &&
        "message" in data.error
      ) {
        console.error("Error in streamed response:", data.error);
        throw new Error(`Error streaming response: ${data.error.message}`);
      }
      throw new Error(
        `Error streaming response: ${JSON.stringify(data.error)}`,
      );
    }

    return data;
  } catch (e) {
    // If the error was thrown by our error check, rethrow it
    if (
      e instanceof Error &&
      e.message.startsWith("Error streaming response:")
    ) {
      throw e;
    }
    // Otherwise it's a JSON parsing error
    throw new Error(`Malformed JSON sent from server: ${json}`);
  }
}

function parseSseLine(line: string): { done: boolean; data: any } {
  if (line.startsWith("data:[DONE]") || line.startsWith("data: [DONE]")) {