问每当mobx `@ `console.log`‘值发生变化时，它就会出现

EN

import { reaction } from 'mobx'

class SomeStore {
    @observable item;
    @observable otherObservable;

    constructor() {
        reaction(
            // The callback will run only on change 
            // of observables described in this function
            () => this.item,
            // You can use whatever observables/computed values in this function
            // without making the function run on an unwanted observables change
            () => {
                if (this.otherObservable) {
                    doSometing();
                }
            }
        )
    }
}