diff --git a/package.json b/package.json
index a3cf7fd..eb70c25 100644
--- a/package.json
+++ b/package.json
@@ -5,7 +5,7 @@
   "private": true,
   "scripts": {
     "build": "npm run clean && npm run build:ts && npm run build:copy",
-    "build:ts": "tsc -p tsconfig.json && tsc -p tsconfig.json -m esnext --outDir dist/esm/ -d false -declarationMap false",
+    "build:ts": "npx tsc -p tsconfig.json && npx tsc -p tsconfig.json -m esnext --outDir dist/esm/ -d false -declarationMap false",
     "build:copy": "copyfiles README.md LICENSE src/package.json dist --flat && copyfiles src/rxjs-operators/package.json dist --up 1",
     "clean": "rm -rf dist",
     "test": "jest",
diff --git a/src/option.ts b/src/option.ts
index 5786302..941b0e7 100644
--- a/src/option.ts
+++ b/src/option.ts
@@ -78,6 +78,10 @@ class NoneImpl implements BaseOption<never> {
         return this;
     }
 
+    or<T2>(other: Option<T2>): Option<T2> {
+        return other;
+    }
+
     andThen<T2>(op: unknown): None {
         return this;
     }
@@ -151,6 +155,10 @@ class SomeImpl<T> implements BaseOption<T> {
         return mapper(this.val);
     }
 
+    or(other: Option<T>): Option<T> {
+        return this;
+    }
+
     toResult<E>(error: E): Ok<T> {
         return Ok(this.val);
     }
@@ -213,7 +221,7 @@ export namespace Option {
             if (option.some) {
                 return option as Some<OptionSomeTypes<T>[number]>;
             } else {
-                return option as None;
+                continue;
             }
         }
 
diff --git a/src/result.ts b/src/result.ts
index c660515..5e4c25b 100644
--- a/src/result.ts
+++ b/src/result.ts
@@ -26,11 +26,11 @@ interface BaseResult<T, E> extends Iterable<T extends Iterable<infer U> ? U : ne
     expect(msg: string): T;
 
     /**
-     * Returns the contained `Ok` value, if does not exist.  Throws an error if it does.
+     * Returns the contained `Err` value, if does not exist.  Throws an error if it does.
      * @param msg the message to throw if Ok value.
      */
-    expectErr(msg: string): T;
-    
+    expectErr(msg: string): E;
+
     /**
      * Returns the contained `Ok` value.
      * Because this function may throw, its use is generally discouraged.