Merge pull request #153 from metaplex-foundation/feat/add-option-wrap…

…Nullish

add wrapNullish() as an available option

.changeset/rare-deers-sparkle.md

@@ -0,0 +1,21 @@
+---
+'@metaplex-foundation/umi-options': minor
+---
+
+`wrapNullable` didn't account for an undefined input and would result in a return value of `some(undefined)` causing `isNone` checks to not pass if `undefined` was the `nullable` value.
+
+```ts
+export const wrapNullable = <T>(nullable: Nullable<T>): Option<T> =>
+  nullable !== null ? some(nullable) : none<T>();
+```
+
+Added a `wrapNullish` function to check for both `null` and undefined which will return the value of `none()` if `null` or `undefined` is the presented `nullish` value.
+
+```ts
+export const wrapNullish = <T>(nullish: Nullish<T>): Option<T> =>
+  nullish !== null && nullish !== undefined ? some(nullish) : none<T>();
+```
+
+- `Nullish` type added.
+- `wrapNullish` function added.
+- Tests for `wrapNullish` added.

packages/umi-options/src/common.ts

@@ -4,6 +4,12 @@
  */
 export type Nullable<T> = T | null;
 
+/**
+ * Defines a type `T` that can also be `null` or `undefined`.
+ * @category Utils — Options
+ */
+export type Nullish<T> = T | null | undefined;
+
 /**
  * An implementation of the Rust Option type in JavaScript.
  * It can be one of the following:

packages/umi-options/src/unwrapOption.ts

@@ -1,4 +1,4 @@
-import { Nullable, Option, isSome, none, some } from './common';
+import { Nullable, Nullish, Option, isSome, none, some } from './common';
 
 /**
  * Unwraps the value of an {@link Option} of type `T`
@@ -24,6 +24,14 @@ export function unwrapOption<T, U = null>(
 export const wrapNullable = <T>(nullable: Nullable<T>): Option<T> =>
   nullable !== null ? some(nullable) : none<T>();
 
+/**
+ * Wraps a nullish value into an {@link Option}.
+ *
+ * @category Utils — Options
+ */
+export const wrapNullish = <T>(nullish: Nullish<T>): Option<T> =>
+  nullish !== null && nullish !== undefined ? some(nullish) : none<T>();
+
 /**
  * Unwraps the value of an {@link Option} of type `T`.
  * If the option is a {@link Some}, it returns its value,

packages/umi-options/test/unwrapOption.test.ts

@@ -1,5 +1,5 @@
 import test from 'ava';
-import { none, some, unwrapOption, wrapNullable } from '../src';
+import { none, some, unwrapOption, wrapNullable, wrapNullish } from '../src';
 
 test('it can unwrap an Option as a Nullable', (t) => {
   t.is(unwrapOption(some(42)), 42);
@@ -34,3 +34,12 @@ test('it can wrap a Nullable as an Option', (t) => {
   t.deepEqual(wrapNullable<string>(null), none<string>());
   t.deepEqual(wrapNullable<number>(null), none<number>());
 });
+
+test('it can wrap a Nullish as an Option', (t) => {
+  t.deepEqual(wrapNullish(42), some(42));
+  t.deepEqual(wrapNullish('hello'), some('hello'));
+  t.deepEqual(wrapNullish(false), some(false));
+  t.deepEqual(wrapNullish(undefined), none<undefined>());
+  t.deepEqual(wrapNullish<string>(null), none<string>());
+  t.deepEqual(wrapNullish<number>(null), none<number>());
+});