clawhub/scripts/security-dataset/convexOutput.ts

export function parseConvexJson(output: string): unknown {
  return parseConvexJsonMatching(output, isJsonValue);
}

export function parseConvexJsonMatching<T>(
  output: string,
  validate: (value: unknown) => value is T,
): T {
  for (let index = 0; index < output.length; index += 1) {
    const char = output[index];
    if (char !== "{" && char !== "[") continue;

    const end = findJsonValueEnd(output, index);
    if (end === null) continue;

    try {
      const parsed: unknown = JSON.parse(output.slice(index, end));
      if (validate(parsed)) return parsed;
    } catch {
      continue;
    }
  }

  throw new Error(`Unable to parse matching Convex JSON output (${output.length} bytes)`);
}

function isJsonValue(value: unknown): value is unknown {
  return value !== undefined;
}

function findJsonValueEnd(output: string, start: number) {
  const first = output[start];
  const stack = first === "{" ? ["}"] : first === "[" ? ["]"] : [];
  let inString = false;
  let escaped = false;

  for (let index = start + 1; index < output.length; index += 1) {
    const char = output[index];

    if (inString) {
      if (escaped) {
        escaped = false;
      } else if (char === "\\") {
        escaped = true;
      } else if (char === '"') {
        inString = false;
      }
      continue;
    }

    if (char === '"') {
      inString = true;
    } else if (char === "{") {
      stack.push("}");
    } else if (char === "[") {
      stack.push("]");
    } else if (char === "}" || char === "]") {
      if (stack.at(-1) !== char) return null;
      stack.pop();
      if (stack.length === 0) return index + 1;
    }
  }

  return null;
}