Custom flag in Nuxt 3

[zerosdev]

How to make a plugin to add custom flag in Nuxt 3 ? I tried this but not working

export default defineNuxtPlugin((nuxtApp) => {
    let webview = useCookie('webview')
    let device = useDevice()
    device.isWebview = webview && webview.value !== null;
})

[Redemption198]

Try with this device.isWebview = webview !== null ? webview.value : false;

[zerosdev]

Try with this device.isWebview = webview !== null ? webview.value : false;

Still not working