feat: adds flattern

README.md

@@ -14,6 +14,7 @@ Heavily inspired by rust [std::option](https://doc.rust-lang.org/std/option/inde
       - [andThen](#andThen)
       - [expect](#expect)
       - [filter](#filter)
+      - [flattern](#flattern)
       - [isNone](#isNone)
       - [isSome](#isSome)
       - [map](#map)
@@ -123,6 +124,14 @@ Option(1).filter(a => a > 0).isSome() // true
 Option(1).filter(a => a > 10).isSome() // false
 ```
 
+#### flattern
+
+Converts from `Option<Option<T>>` to `Option<T>`
+
+```ts
+Option(Some(100)).flattern() // Some(100)
+```
+
 #### isNone
 
 Returns if has not a value

src/Option.ts

@@ -89,6 +89,24 @@ class OptionLike<T> {
     return predicateresult ? this : (None() as any);
   }
 
+  /**
+   * Converts from `Option<Option<T>>` to `Option<T>`
+   *
+   * ```ts
+   * Option(Some(100)).flattern() // Some(100)
+   * ```
+   *
+   * @returns {OptionLike<T>}
+   * @memberof OptionLike
+   */
+  public flattern(): OptionLike<T> {
+    if (this.value instanceof OptionLike) {
+      return this.value;
+    }
+
+    return this;
+  }
+
   /**
    * Returns if has not a value
    *

src/__tests__/Option.spec.ts

@@ -118,4 +118,8 @@ describe(`Option`, () => {
     expect(Some(100).transpose()).toStrictEqual(Ok(Some(100)));
     expect(None().transpose()).toStrictEqual(Ok(None()));
   });
+
+  it("Converts from `Option<Option<T>>` to `Option<T>`", () => {
+    expect(Option(Some(100)).flattern()).toStrictEqual(Some(100));
+  });
 });