redux - 如何通过索引获取对象 immutable.js

Question

在 Immutable.js 中，我如何通过索引从列表中获取对象并设置属性然后更新整个列表。

状态是一组名为艺术家的对象。

[{ id: 1, selected: false}, { id: 2, selected: false}]

现在我想在索引 0 处设置 selected = true

我试过:

  const artistItem = state.get(action.payload.index).set({ selected: true });
  const artists = state.get('artists').set(action.payload.index, artistItem);

如何在不覆盖其他属性的情况下实现这一目标？

Answer 1

如果你的状态真的很像

[{ id: 1, selected: false}, { id: 2, selected: false}]

我相信你想使用 List#update :

let state = Immutable.fromJS([
    {id: 1, selected: false},
    {id: 2, selected: false}
]);

state = state.update(0, (artist) => artist.set('selected', true));
console.log(state); // [{id: 1, selected: true}, {id: 2, selected: false}]

// Note that this is equivalent to:
state = state.set(0, state.get(0).set('selected'));

但是从你的代码看来你的状态实际上看起来更像

{ artists: [{ id: 1, selected: false}, { id: 2, selected: false}] }

如果是这种情况，您将需要使用 Map#updateIn :

let state = Immutable.fromJS({
    artists: [
       {id: 1, selected: false},
       {id: 2, selected: false}
    ]
});

state = state.updateIn(['artists', 0], (artist) => artist.set('selected', true));
console.log(state); //{artists: [{id: 1, selected: true}, {id: 2, selected: false}]

// Note that this is equivalent to:
state = state.set(
  'artists',
  state.get(artists).set(
    0,
    state.get(artists).get(0).set('selected', true)
));