SOURCE

const app = document.getElementById('app')

const data = {text: 'hello'}

const bucket = new Set()

const proxy = new Proxy(data, {
    get(target, key){
        bucket.add(effect);
        return target[key];
    },
    set(target, key, val){
        target[key] = val;
        bucket.forEach(fn=>fn())
        return true;
    }
})

function effect(){
    app.innerHTML = proxy.text;
}

effect()

proxy.text = 'world'

<div id="app"></div>