serialize.ts

  /**
   * Destroys circular references for use with JSON serialization
   *
   * @param from - Source object or array
   * @param seen - Array with object already serialized. Set to `[]` (empty array)
   *   when using this function!
   */
  private static _destroyCircular(from: any, seen: any[]) {
    let to: any;
    if (Array.isArray(from)) {
      to = [];
    } else {
      to = {};
    }

    seen.push(from);

    Object.keys(from).forEach((key) => {
      const value = from[key];

      if (typeof value === "function") {
        // No Logging of functions
        return;
      }

      if (typeof value === "symbol") {
        // Use the symbol's name
        to[key] = value.toString();
        return;
      }

      if (!value || typeof value !== "object") {
        // Simple data types
        to[key] = value;
        return;
      }

      if (typeof value === "object" && typeof value.toJSON === "function") {
        to[key] = value.toJSON();
        return;
      }

      if (!seen.includes(from[key])) {
        to[key] = Logger._destroyCircular(from[key], seen.slice(0));
        return;
      }

      to[key] = "[Circular]";
    });

    if (typeof from.name === "string") {
      to.name = from.name;
    }

    if (typeof from.message === "string") {
      to.message = from.message;
    }

    if (typeof from.stack === "string") {
      to.stack = from.stack;
    }

    return to;
  }

  /**
   * Helper function to serialize class instances to plain objects for logging
   *
   * @param key - Property key
   * @param value - Property value
   *
   * @example
   * const myObj = { foo: "bar" };
   * const str = JSON.stringify(myObj, serializeObj, "\t");
   */
  private static _serializeObj(key: any, value: any): any {
    if (typeof value === "object" && value !== null) {
      return Logger._destroyCircular(value, []);
    }
    return value;
  }

  /**
   * Like `JSON.stringify` but handles circular references and serializes error objects.
   */
  static stringify(value: any, space?: string | number | undefined): string {
    return JSON.stringify(value, Logger._serializeObj, space);
  }