Type Alias Result<T, E>

A classic Result type that can either be Ok or Err.

Result wraps a value under the value field, and provides convenience methods for checking if Result is Ok or Err:

const answer: Result<number, never> = Ok(42);

answer.isOk(); // => true
answer.isErr(); // => false
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If the function returns a compatible Result type, instead of unwrapping the result, and wrapping it back, map and mapErr methods can be used:

function someFunctionA(x: number): Result<number, string> {
  if (0 === x % 2)
    return Err("number was even");
  return Ok(x);
}

function someFunctionB(num: number): Result<number, string> {
    return someFunctionA(num).map((x) => x + 1);
}
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