Simple store with MobX

TaskListStore.js

import { observable, action } from 'mobx'

class TaskListStore {

  @observable list = [
    { title: 'Go to the office', isFinished: true },
    { title: 'Prepare tasks for today', isFinished: false },
    { title: 'Team meeting', isFinished: false },
    { title: 'Commit tasks changed', isFinished: false }
  ]

  @action finishItem (index) {
    const copiedList = this.list.slice()
    const isFinished = copiedList[index].isFinished
    if (isFinished) return

    copiedList[index].isFinished = true
    this.list = copiedList // update store by re-assigning
  }

  @action deleteItem (index) {
    this.list = this.list.filter((item, i) => i != index)
  }
}

const store = new TaskListStore()
export default store