VueJs

autorun.js

var subscribers = []
var activeJob = null

var a = 3
var state = {
    get a () {
        if(subscribers.indexOf(activeJob) < 0){
            subscribers.push(activeJob)
        }
        return a
    },
    set a (newValue){
        a = newValue
        subscribers.forEach(job => job())
    }
}

var autorun = update => {

    function job() {
        activeJob = job
        update()
        activeJob = null
    }

    job()
}

autorun(() => {
    console.log((state.a * 10))
})