🐨 Adds result types - Result, Error & Ok

app/src/lib/utilities/result/err.ts

@@ -0,0 +1,36 @@
+export class Err<T> {
+  #inner: T
+
+  constructor(inner: T) {
+    this.#inner = inner
+  }
+
+  get inner(): T {
+    return this.#inner
+  }
+
+  /**
+   * Type guard for `Ok`
+   * @returns `true` if `Ok`; `false` if `Err`
+   */
+  isOk(): false {
+    return false
+  }
+
+  /**
+   * Type guard for `Err`
+   * @returns `true` if `Err`; `false` if `Ok`
+   */
+  isErr(): this is Err<T> {
+    return true
+  }
+
+  /**
+   * Create an `Err`
+   * @param inner
+   * @returns `Err(inner)`
+   */
+  static new<E>(inner: E): Err<E> {
+    return new Err<E>(inner)
+  }
+}