diff --git a/.github/workflows/npm-publish.yml b/.github/workflows/npm-publish.yml
new file mode 100644
index 0000000..545ae30
--- /dev/null
+++ b/.github/workflows/npm-publish.yml
@@ -0,0 +1,20 @@
+name: NPM publish package
+
+on:
+    release:
+        types: [created]
+
+jobs:
+    publish-npm:
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@v4
+            - uses: actions/setup-node@v4
+              with:
+                  node-version: 20
+                  registry-url: https://registry.npmjs.org/
+            - run: npm ci
+            - run: npm run build
+            - run: npm run publish-npm -- --provenance
+              env:
+                  NODE_AUTH_TOKEN: ${{secrets.npm_token}}
diff --git a/.github/workflows/quality-check.yml b/.github/workflows/quality-check.yml
new file mode 100644
index 0000000..0fbd21f
--- /dev/null
+++ b/.github/workflows/quality-check.yml
@@ -0,0 +1,22 @@
+name: Quality check
+
+on:
+    push:
+        branches: [ "main" ]
+    pull_request:
+        branches: [ "main" ]
+
+jobs:
+    build:
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@v4
+            - name: Use Node.js
+              uses: actions/setup-node@v4
+              with:
+                  node-version: 20
+                  cache: 'npm'
+            - run: npm ci
+            - run: npm run compile
+            - run: npm run lint
+            - run: npm run test
diff --git a/package.json b/package.json
index 550da1b..fed5532 100644
--- a/package.json
+++ b/package.json
@@ -1,12 +1,12 @@
 {
     "name": "@arnonym/result",
-    "version": "1.0.2",
+    "version": "1.0.3",
     "description": "Result type for TypeScript inspired by Rust",
     "main": "dist/index.js",
     "types": "dist/index.d.ts",
     "scripts": {
-        "build": "rm -rf dist; npm run check && vite build --mode esm && vite build --mode cjs",
-        "publish-npm": "npm run build && npm publish --access public",
+        "build": "rm -rf dist; vite build --mode esm && vite build --mode cjs",
+        "publish-npm": "npm publish --access public",
         "compile": "tsc --noEmit",
         "test": "jest",
         "lint": "eslint",
diff --git a/src/index.ts b/src/index.ts
index 8f4b755..9c82208 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,2 +1,2 @@
-export { Result, Match, Ok, Err } from './result';
+export { Result, type Match, type Ok, type Err } from './result';
 export { pipe } from './pipe';
diff --git a/src/result.test.ts b/src/result.test.ts
index 83667d0..38e2a58 100644
--- a/src/result.test.ts
+++ b/src/result.test.ts
@@ -214,7 +214,41 @@ describe('result', () => {
             const val = Result.err(-1);
             expect(() => {
                 val.unwrap();
-            }).toThrow();
+            }).toThrow("-1");
+        });
+    });
+
+    describe('expect', () => {
+        test('should "expect" ok', () => {
+            const val = Result.ok(3);
+            const val2 = val.expect("You did it wrong!");
+            expect(val2).toBe(3);
+        });
+        test('should not "expect" err but throw with string', () => {
+            const val = Result.err(-1);
+            expect(() => {
+                val.expect("You did it wrong!");
+            }).toThrow(new Error("You did it wrong!"));
+        });
+        test('should not "expect" err but throw with function', () => {
+            const val = Result.err(-1);
+            expect(() => {
+                val.expect(e => `You did it wrong: ${e}`);
+            }).toThrow(new Error("You did it wrong: -1"));
+        });
+    });
+
+    describe('unwrapErr', () => {
+        test('should "unwrapErr" err', () => {
+            const val = Result.err(3);
+            const val2 = val.unwrapErr();
+            expect(val2).toBe(3);
+        });
+        test('should not "unwrapErr" err but throw', () => {
+            const val = Result.ok(-2);
+            expect(() => {
+                val.unwrapErr();
+            }).toThrow("Tried to unwrapErr on value: -2");
         });
     });
 
@@ -441,7 +475,7 @@ describe('result', () => {
         });
         test('assertOk on error should throw', () => {
             const result = Result.err(3);
-            expect(() => Result.assertOk(result)).toThrow();
+            expect(() => Result.assertOk(result)).toThrow("Expected Ok, got Err: 3");
         });
         test('assertErr on err', () => {
             const result = Result.err(3);
@@ -450,7 +484,7 @@ describe('result', () => {
         });
         test('assertOk on error should throw', () => {
             const result = Result.ok(3);
-            expect(() => Result.assertErr(result)).toThrow();
+            expect(() => Result.assertErr(result)).toThrow("Expected Err, got Ok: 3");
         });
     });
 
diff --git a/src/result.ts b/src/result.ts
index 7566a96..be5f7fc 100644
--- a/src/result.ts
+++ b/src/result.ts
@@ -17,6 +17,8 @@ type IncludesType<T extends Array<unknown>, S> = {
 
 export type NeverIfExistingInUnion<T extends Array<unknown>> = IncludesType<T, never> extends true ? never : T;
 
+type ExpectMessage<E> = string | ((err: E) => string);
+
 interface Functions<O, E> {
     isOk: () => this is Ok<O>;
     isErr: () => this is Err<E>;
@@ -24,6 +26,8 @@ interface Functions<O, E> {
     andThen: <NO, NE>(fn: (value: O) => Result<NO, NE>) => Result<NO, E | NE>;
     mapErr: <NE>(fn: (err: E) => NE) => Result<O, NE>;
     unwrap: () => O;
+    unwrapErr: () => E;
+    expect: (message: ExpectMessage<E>) => O;
     unwrapOr: <R1>(def: R1) => O | R1;
     unwrapOrElse: <R1>(def: (err: E) => R1) => O | R1;
     or: <R1>(def: R1) => Result<O | R1, never>;
@@ -81,7 +85,24 @@ function unwrap<O, E>(data: Result<O, E>): O {
     if (data.isOk()) {
         return data.value;
     }
-    throw new Error(`Tried to unwrap error: ${data.err}`);
+    throw data.err;
+}
+
+function unwrapErr<O, E>(data: Result<O, E>): E {
+    if (data.isErr()) {
+        return data.err;
+    }
+    throw new Error(`Tried to unwrapErr on value: ${data.value}`);
+}
+
+function expect<O, E>(message: ExpectMessage<E>): (data: Result<O, E>) => O {
+    return data => {
+        if (data.isOk()) {
+            return data.value;
+        }
+        const m = typeof message === 'function' ? message(data.err) : message;
+        throw new Error(m);
+    }
 }
 
 function unwrapOr<R1>(def: R1): <O, E>(data: Result<O, E>) => O | R1 {
@@ -139,6 +160,14 @@ class InternalResult<O, E> implements Functions<O, E> {
         return unwrap<O, E>(this as unknown as Result<O, E>);
     }
 
+    unwrapErr() {
+        return unwrapErr<O, E>(this as unknown as Result<O, E>);
+    }
+
+    expect(message: ExpectMessage<E>) {
+        return expect<O, E>(message)(this as unknown as Result<O, E>);
+    }
+
     unwrapOr<R1>(def: R1) {
         return unwrapOr<R1>(def)(this as unknown as Result<O, E>);
     }