The useMeta composable is part of Quasar Meta Plugin. If you haven’t dug into it by now, please have a first read there.
Syntax
For static meta configuration (non-reactive):
import { useMeta } from 'quasar'
setup () {
  useMeta({ /* meta config */ })
}content_paste
For dynamic meta configuration (reactive):
import { useMeta } from 'quasar'
setup () {
  // essentially acting as a computed property
  useMeta(() => {
    // compute or reference other stuff
    // in your component
    // then return:
    return { /* meta config */ }
  })
}content_paste
Example
<script>
import { useMeta } from 'quasar'
export default {
  setup () {
    const title = ref('Some title') // we define the "title" prop
    // NOTICE the parameter here is a function
    // Under the hood, it is converted to a Vue computed prop for reactivity
    useMeta(() => {
      return {
        // whenever "title" from above changes, your meta will automatically update
        title: title.value
      }
    })
    function setAnotherTitle () {
      title.value = 'Another title' // will automatically trigger a Meta update due to the binding
    }
    return {
      setAnotherTitle
    }
  }
}
</script>content_paste