import { Options } from "https://deno.land/x/eitherway@0.10.0/mod.ts";
const { all } = Options;
Use this to transpose Option<T>[] to Some<T[]> if all elements are
Some<T>
If one element is None, or if the input array/tuple is empty, None
is immediately returned
This function retains type constraints like readonly on the input array
or tuple and is able to infer variadic tuples
Examples
Example 1
Example 1
import { assert } from "./assert.ts";
import { Option, Options, None, Some } from "./option.ts";
type StrictTuple = Readonly<[string, number, boolean]>;
const tuple = [
Option("some" as string),
Option(1 as number),
Option(true as boolean),
] as const;
const empty: Option<string>[] = [];
const encode = JSON.stringify;
const someTuple: Option<StrictTuple> = Options.all(tuple);
const emptyIsNone : Option<string[]> = Options.all(empty);
if (someTuple.isNone() || emptyIsNone.isSome()) {
throw TypeError("Unreachable in this example");
}
const unwrapped: StrictTuple = someTuple.unwrap();
const undef: undefined = emptyIsNone.unwrap();
assert(someTuple.isSome() === true);
assert(emptyIsNone.isNone() === true);
assert(encode(unwrapped) === encode(tuple));
assert(undef === undefined);
Type Parameters
O extends ReadonlyArray<Option<unknown>>
Parameters
opts: O