either-utils

Usage

const ok = success(42)
const fail = error('Something went wrong')

// Type guards
if (isSuccess(ok)) {
  console.log('Data:', ok.data)
}

if (isError(fail)) {
  console.error('Error:', fail.error)
}

// Map success
const mapped = mapSuccess(ok, n => n * 2)
// => { success: true, data: 84, error: null }

const skipped = mapSuccess(fail, n => n * 2)
// => { success: false, error: 'Something went wrong', data: null }

// Chain (flatMap) success
const chained = chainSuccess(ok, n =>
  n > 0 ? success(n + 1) : error('Invalid')
)
// => { success: true, data: 43 }

const chainedError = chainSuccess(ok, n =>
  error('Force fail')
)
// => { success: false, error: 'Force fail' }