@skarab/result

@skarab/result is a TypeScript library providing a robust pattern for handling success and failure outcomes in a functional programming style. Utilizing advanced TypeScript features, it allows developers to create expressive, type-safe APIs that clearly distinguish between successful results and errors.

Features

• Type-Safe Success and Failure Handling: Clearly differentiate between success and failure cases using TypeScript types.
• Functional Approach: Embrace a functional programming style for handling results.
• Easy to Use: Simple API with powerful type inference.

Installation

To install the package, use pnpm, npm or yarn:

Installation

pnpm add @skarab/result

Usage

Here's a basic example of how to use @skarab/result:

import { success, failure, isSuccess, unwrap } from '@skarab/result';

function performOperation(): Result<number, Error> {
  // some operation
  if (/* operation successful */) {
    return success(42);
  } else {
    return failure(new Error('Operation failed'));
  }
}

const result = performOperation();

if (isSuccess(result)) {
  console.log('Success with value:', unwrap(result));
} else {
  console.log('Failure with error:', unwrap(result));
}

API Documentation

Types

Success<SuccessValue>

• A type representing a successful result.
• Contains a value of type SuccessValue.
• Indexed by a unique success symbol, ensuring type safety and avoiding property clashes.

Failure<FailureValue>

• A type representing a failure result.
• Contains a value of type FailureValue.
• Indexed by a unique failure symbol, providing clear differentiation from the Success type.

Result<SuccessValue, FailureValue>

• A union type representing either a success or a failure.
• Encapsulates Success<SuccessValue> and Failure<FailureValue>.

Functions

success<SuccessValue>(value: SuccessValue): Success<SuccessValue>

• Creates a success result containing the provided value.
• Useful for wrapping successful outcomes in a type-safe manner.
• Parameters:
  • value: The value to be associated with the success.

failure<FailureValue>(value: FailureValue): Failure<FailureValue>

• Creates a failure result containing the provided value.
• Ideal for expressing error states or unsuccessful outcomes.
• Parameters:
  • value: The value to be associated with the failure.

isSuccess<SuccessValue>(result: Result<SuccessValue, unknown>): result is Success<SuccessValue>

• A type guard function that checks if a given result is a success.
• Returns true if the result is a success, otherwise false.
• Helps in narrowing down the type of the result to Success<SuccessValue> when true.

isFailure<FailureValue>(result: Result<unknown, FailureValue>): result is Failure<FailureValue>

• A type guard function that checks if a given result is a failure.
• Returns true if the result is a failure, otherwise false.
• Assists in type narrowing to Failure<FailureValue> when the result is a failure.

unwrap<SuccessValue, FailureValue>(result: Result<SuccessValue, FailureValue>): FailureValue | SuccessValue

• Extracts the value from a success or failure result.
• Simplifies the process of accessing the underlying value of a result.
• Parameters:
  • result: The Result instance from which the value should be unwrapped.

Contributing

Contributions are welcome! Please open an issue or submit a pull request for any features or fixes.

License

This project is licensed under the MIT License.

Scaffolded with @skarab/skaffold