React - 如何映射嵌套对象值？ [英] React - how to map nested object values?

问题描述

我只是想在状态对象中映射嵌套值。数据结构如下所示：

I am just trying to map nested values inside of a state object. The data structure looks like so:

I想要映射每个里程碑名称，然后映射该里程碑内的所有任务。现在我正在尝试使用嵌套的地图函数，但我不确定我是否可以这样做。

I want to map each milestone name and then all tasks inside of that milestone. Right now I am trying to do so with nested map functions but I am not sure if I can do this.

渲染方法如下所示：

render() {
    return(
      <div>
        {Object.keys(this.state.dataGoal).map( key => {
            return <div key={key}>>

                     <header className="header">
                       <h1>{this.state.dataGoal[key].name}</h1>
                     </header>
                     <Wave />

                     <main className="content">
                       <p>{this.state.dataGoal[key].description}</p>

                         {Object.keys(this.state.dataGoal[key].milestones).map( (milestone, innerIndex) => {
                             return <div key={milestone}>
                                      {milestone}
                                      <p>Index: {innerIndex}</p>
                                    </div>
                         })}
                     </main>

                   </div>
        })}
      </div>
    );
  }

我认为我可以以某种方式通过传递这行代码的内部索引： {Object.keys（this.state.dataGoal [key] .milestones）所以看起来像这样： { Object.keys（this.state.dataGoal [key] .milestones [innerIndex]）。

I think that I could somehow achieve that result by passing the inner index to this line of code: {Object.keys(this.state.dataGoal[key].milestones) so it would look like: {Object.keys(this.state.dataGoal[key].milestones[innerIndex]).

但我不知道如何通过 innerIndex up。我还尝试通过 {milestone.name} 获取里程碑名称，但这也不起作用。我想这是因为我必须指定密钥。

But I am not sure how to pass the innerIndex up. I have also tried to get the milestone name by {milestone.name} but that doesn't work either. I guess that's because I have to specify the key.

有人有想法吗？或者我应该以完全不同的方式映射整个对象？

Does anybody have an idea? Or should I map the whole object in a totally different way?

很高兴任何帮助，
Jakub

Glad for any help, Jakub

推荐答案

您可以使用嵌套地图映射里程碑，然后映射任务数组：

You can use nested maps to map over the milestones and then the tasks array:

render() {
  return (
    <div>
      {Object.keys(this.state.dataGoal.milestones).map((milestone) => {
        return {this.state.dataGoal.milestones[milestone].tasks.map((task, idx) => {
          return (
          //whatever you wish to do with the task item
          )
        })
      })}
    </div>
  )
}

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