$watch throw erros inside init function on stores

[lightsyr]

When i use this.$watch inside a init function, js console throw me that error:

document.addEventListener('alpine:init', () => {
  Alpine.store('app', {
    this.value = ""
    init(){
     this.$watch("value", ()=>{ console.log("test")})
    }
  })
 
})

Uncaught (in promise) TypeError: this.$watch is not a function
at Proxy.init (app.js:109:9)
at Object.Tr [as store] (cdn.min.js:5:13568)
at HTMLDocument.<anonymous> (app.js:33:9)
at q (cdn.min.js:5:3584)
at Object.ur [as start] (cdn.min.js:5:4119)
at cdn.min.js:5:36293

[ekwoka]

Magics (Except $perist) do not work in stores. use Alpine.effect instead.

[lightsyr]

ohhh, thank you!