option-t/esm/nullable/operators/zip_with.js

A toolkit of Nullable/Option/Result type implementation in ECMAScript. Their APIs are inspired by Rust's `Option<T>` and `Result<T, E>`.

import { isNull, expectNotNull } from '../core/nullable.js';
import { ERR_MSG_TRANSFORMER_MUST_NOT_RETURN_NO_VAL_FOR_NULLABLE } from '../internal/error_message.js';
/**
 *  Zips _self_ and another `Nullable` with function _transformer_.
 *  If _self_ is `T` and _other_ is `U`, this method returns the result of _transformer_.
 *  Otherwise, `null` is returned.
 *
 *  @throws {TypeError}
 *      Throws if the _transformer_ returns `null`.
 */
export function zipWithForNullable(self, other, transformer) {
    if (isNull(self) || isNull(other)) {
        return null;
    }
    const result = transformer(self, other);
    const checked = expectNotNull(result, ERR_MSG_TRANSFORMER_MUST_NOT_RETURN_NO_VAL_FOR_NULLABLE);
    return checked;
}