setstate object:{array:[]} in reactjs 如何在 state 對象**中的數組中添加**鍵和值？

Question

state object 中的數組內的鍵和值

this.state = { 頻率：{ 天：[]，開始日期：“”，自定義日期：“”}，}；

如何在 days 數組中添加關鍵廣告值？

Answer 1

您可以使用setState修改您的 state，如下所示：

this.setState({frequency: {...this.state.frequency, days: [...this.state.frequency.days, day]}});

Answer 2

function addKeyValue(key, value) {

  this.setState(state => ({
    ...state,
    frequency: {
       ...state.frequency,
       days: [...state.frequency.days, {[key]: value}]
    }
  })
}

- 編輯

刪除密鑰有點棘手。

function removeKeyValue(key, value) {

  this.setState(state => {
    const days = state.frequency.days;
    const dayIndex = days.findIndex(pr => pr[key] === value);
    const day = {...days[dayIndex]};
    delete day[key];

    return {
      ...state,
      frequency: {
         ...state.frequency,
         days: [...days.slice(0, dayIndex),
            day,
            ...days.slice(dayIndex + 1)]
      }
    }
  }
}