declaration vue 3 variables

1. To declare a variable in Vue 3, you can use the "data" function within the "data" option of the component. For example, you can declare a variable called "message" by returning an object with "message" as a property inside the "data" function.

2. Another way to declare a variable in Vue 3 is by using the "ref" function. This allows you to create a reactive reference to a value. For instance, you can declare a variable called "count" by using the "ref" function and passing the initial value as an argument.

3. Additionally, you can declare a reactive variable in Vue 3 by using the "reactive" function. This allows you to create a reactive object with the properties you specify. For example, you can declare a variable called "userInfo" by using the "reactive" function and passing an object with the desired properties.

These are the three main ways to declare variables in Vue 3, each with its own specific use case and advantages.