option-t
Version:
A toolkit of Nullable/Option/Result type implementation in ECMAScript. Their APIs are inspired by Rust's `Option<T>` and `Result<T, E>`.
17 lines (16 loc) • 446 B
JavaScript
/**
* Returns `None` if the _input_ is `None`,
* otherwise calls _transformer_ with the value and returns the result.
*
* XXX:
* Some languages call this operation flatmap.
* But we don't provide `flatMap()` as alias of this function
* to sort with other APIs.
*/
export function andThenForOption(input, transformer) {
if (!input.ok) {
return input;
}
const result = transformer(input.val);
return result;
}