Implementing onBeforeMount Lifecycle Hook in a Vue Component

The onBeforeMount lifecycle hook in Vue 3 allows you to run code before the component is mounted to the DOM. This is useful for initializing data, setting up subscriptions, or performing any other setup tasks that need to happen before the component becomes visible. This challenge asks you to create a Vue component that utilizes onBeforeMount to demonstrate its functionality.

Problem Description

You are tasked with creating a Vue component called MyComponent that displays a message indicating when it's being initialized. The component should have a message property that is initially set to "Initializing..." and then updated to "Component mounted!" after the component is mounted. This update should happen before the component is mounted to the DOM, using the onBeforeMount lifecycle hook.

Key Requirements:

• The component must use the Composition API.
• The message property must be reactive.
• The onBeforeMount hook must be used to update the message property.
• The component must display the current value of the message property in its template.

Expected Behavior:

When the component is created, the initial message displayed should be "Initializing...". Immediately before the component is mounted to the DOM, the message should be updated to "Component mounted!". The displayed message should remain "Component mounted!" after the component is mounted.

Edge Cases to Consider:

• Ensure the message update happens before the component is rendered for the first time.
• Consider how the reactive nature of message affects the component's rendering.

Examples

Example 1:

Input: A Vue component using Composition API and onBeforeMount.
Output: The component initially displays "Initializing...", then immediately updates to "Component mounted!" before rendering.
Explanation: The onBeforeMount hook executes before the component is mounted, allowing the message to be updated before the initial render.

Example 2:

Input: A Vue component with a complex setup function.
Output: The message is still updated correctly within the onBeforeMount hook, regardless of the complexity of the setup function.
Explanation: The onBeforeMount hook is executed regardless of the complexity of the setup function.

Constraints

• The component must be written in TypeScript.
• The component must use the Composition API.
• The solution should be concise and readable.
• The component should not rely on any external libraries.
• The component should be a functional component.

Notes

• Remember that onBeforeMount is called before the component is mounted to the DOM.
• The message property should be reactive so that changes trigger re-renders.
• Consider using ref to create a reactive variable for the message.
• Focus on demonstrating the correct usage of onBeforeMount to achieve the desired behavior. The component's overall functionality is secondary to demonstrating the lifecycle hook.