@rbxts/jsnatives


constructor

Creates a new Error object.

Signature

new Error(message?: string): Error
Error(message?: string): Error

Description

The Error constructor creates a new error object. When called as a function, it behaves the same as when called as a constructor, returning a new Error object in both cases.

Parameters

Return value

Examples

Basic Usage

// Creating an error with a constructor
const error1 = new Error("Something went wrong");
print(error1.name);    // "Error"
print(error1.message); // "Something went wrong"


// Creating an error with a function call
const error2 = Error("Another error");
print(error2.name);    // "Error"
print(error2.message); // "Another error"


// Creating an error without a message
const error3 = new Error();
print(error3.message); // "" (empty string)

Creating and Throwing Errors

function divide(a: number, b: number): number {
  if (b === 0) {
    throw new Error("Division by zero");
  }
  return a / b;
}


try {
  const result = divide(10, 0);
} catch (err) {
  print(`Caught an error: ${err.message}`);
  // Outputs: "Caught an error: Division by zero"
}

Custom Parameter Validation

function validateParameters(options: unknown): void {
  if (options === undefined || options === null) {
    throw new Error("Options parameter is required");
  }


  if (typeof options !== "object") {
    throw new Error("Options must be an object");
  }


  // More validation...
}


try {
  validateParameters("not an object");
} catch (err) {
  print(err.message); // "Options must be an object"
}

Enhancing Error Information

// Add context to errors
function processUserData(userId: string) {
  try {
    // Simulate an operation that might fail
    if (!userId) {
      throw new Error("Invalid user ID");
    }


    // More processing...


  } catch (err) {
    // Add context to the original error
    const enhancedError = new Error(
      `Failed to process user data: ${err.message}`
    );


    // Can also preserve original stack if available
    if (err.stack) {
      enhancedError.stack = err.stack;
    }


    throw enhancedError;
  }
}

Setting Custom Properties

// Create an error with additional properties
function createCustomError(
  message: string,
  code: number,
  details?: unknown
): Error {
  const error = new Error(message);


  // Add custom properties to the error object
  // Note: TypeScript doesn't know about these properties by default
  (error as any).code = code;


  if (details !== undefined) {
    (error as any).details = details;
  }


  return error;
}


// Usage
try {
  throw createCustomError("Resource not found", 404, {
    resourceType: "user",
    requestedId: "123"
  });
} catch (err) {
  print(err.message);  // "Resource not found"
  print((err as any).code);  // 404


  if ((err as any).details) {
    print(`Resource type: ${(err as any).details.resourceType}`);
    // "Resource type: user"
  }
}