Integrating TypeScript for Enhanced Type Safety in Vue Projects

# Title: Integrating TypeScript for Enhanced Type Safety in Vue Projects
# Description: Best practices for incorporating TypeScript into Vue.js applications to catch errors early and improve code quality.
# Category: Vue Cursor Rules

## TypeScript Integration

- **Enable TypeScript in Vue Projects**: Utilize the Vue CLI to scaffold new projects with TypeScript support by selecting the TypeScript option during project creation.

- **Use `<script lang="ts">` in Single File Components (SFCs)**: Ensure all Vue components are written in TypeScript by specifying `lang="ts"` in the `<script>` tag.

## Type Definitions

- **Define Interfaces for Props and State**: Create explicit interfaces for component props and state to enhance type safety and code readability.

  ```typescript
  interface User {
    id: number;
    name: string;
  }

  export default defineComponent({
    props: {
      user: {
        type: Object as PropType<User>,
        required: true,
      },
    },
  });
  ```

## Composition API

- **Adopt the Composition API**: Leverage Vue 3's Composition API for better organization and reuse of logic, which aligns well with TypeScript's capabilities.

  ```typescript
  import { defineComponent, ref } from 'vue';

  export default defineComponent({
    setup() {
      const count = ref<number>(0);
      const increment = () => {
        count.value++;
      };
      return { count, increment };
    },
  });
  ```

## Vuex with TypeScript

- **Implement Vuex with TypeScript**: Define strict types for Vuex state, mutations, actions, and getters to ensure type safety across the store.

  ```typescript
  import { createStore } from 'vuex';

  interface State {
    count: number;
  }

  const store = createStore<State>({
    state: {
      count: 0,
    },
    mutations: {
      increment(state) {
        state.count++;
      },
    },
  });

  export default store;
  ```

## TypeScript Configuration

- **Enable Strict Type Checking**: Configure `tsconfig.json` to enforce strict type checks, catching potential errors during development.

  ```json
  {
    "compilerOptions": {
      "strict": true,
      "noImplicitAny": true,
      "strictNullChecks": true,
      "strictFunctionTypes": true,
      "strictPropertyInitialization": true
    }
  }
  ```

## Tooling

- **Utilize IDE Support**: Use IDEs like Visual Studio Code with the official Vue extension to benefit from enhanced TypeScript support, including syntax highlighting and IntelliSense.

## Testing

- **Incorporate TypeScript in Testing**: Use testing frameworks compatible with TypeScript, such as Vitest, to ensure components and logic are thoroughly tested.

  ```typescript
  import { describe, it, expect } from 'vitest';
  import { mount } from '@vue/test-utils';
  import MyComponent from '@/components/MyComponent.vue';

  describe('MyComponent', () => {
    it('renders correctly', () => {
      const wrapper = mount(MyComponent);
      expect(wrapper.text()).toContain('Hello, World!');
    });
  });
  ```

## Best Practices

- **Avoid Using `v-html`**: Refrain from using the `v-html` directive to prevent potential security vulnerabilities.

- **Sanitize User Input**: Always sanitize user input to protect against injection attacks.

- **Keep Dependencies Updated**: Regularly update project dependencies to maintain security and compatibility.

- **Validate User Input**: Implement validation mechanisms to ensure user input meets expected criteria.