angular - 错误类型错误 : Cannot assign to read only property 'isSelected' of object '[object Object]'

Question

我只想在克隆后更新我的 NgRx 存储对象中数组元素的属性值以避免突变但没有成功。
这是 reducer 代码:

on(
    myActions.elementDeselected,
    (state, { desiredId}) => {
    const childArrayCopy=[...state.selectedObject.childArray.slice(0)];
    const childArray = childArrayCopy.map(arrayElement=> {
        if (arrayElement.id === desiredId) {
          arrayElement.isSelected = false;
          return arrayElement;
        }
        return arrayElement;
      });

      return {
        ...state,
        selectedObject: {
          ...state.selectedObject,
          ...childArray
        }
      };
    }
  ),

Answer 1

自 arrayElement是只读的，你也必须复制它:

const childArray = childArrayCopy.map(arrayElement=> {
  if (arrayElement.id === desiredId) {
    arrayElement = {...arrayElement, isSelected: false}; // <===
  }
  return arrayElement;
});

使用扩展的对象属性版本创建一个新对象，其中包含旧对象属性的副本，然后更新 isSelected成为 false .