以不变的方式更新数组中的对象之一 [英] Update one of the objects in array, in an immutable way

问题描述

在React的this.state中，我有一个名为formErrors的属性，其中包含以下动态对象数组.

In React's this.state I have a property called formErrors containing the following dynamic array of objects.

[
  {fieldName: 'title', valid: false}, 
  {fieldName: 'description', valid: true},
  {fieldName: 'cityId', valid: false},
  {fieldName: 'hostDescription', valid: false},
]

假设我需要将具有fieldName cityId的状态对象更新为true的有效值.

Let's say I would need to update state's object having the fieldName cityId to the valid value of true.

最简单或最常见的解决方法是什么?

我可以使用任何一种库 immutability-helper ， immutable-js 等或ES6.我已经尝试并在Google上搜索了4个多小时，但仍然无法绕开它.非常感谢您的帮助.

I'm OK to use any of the libraries immutability-helper, immutable-js etc or ES6. I've tried and googled this for over 4 hours, and still cannot wrap my head around it. Would be extremely grateful for some help.

推荐答案

您可以使用map迭代数据并检查fieldName，如果fieldName是cityId，则需要更改值并返回新对象，否则只需return相同的object.

You can use map to iterate the data and check for the fieldName, if fieldName is cityId then you need to change the value and return a new object otherwise just return the same object.

这样写:

var data = [
    {fieldName: 'title', valid: false}, 
    {fieldName: 'description', valid: true},
    {fieldName: 'cityId', valid: false},
    {fieldName: 'hostDescription', valid: false},
]

var newData = data.map(el => {
                  if(el.fieldName == 'cityId')
                     return Object.assign({}, el, {valid:true})
                  return el
              });

this.setState({ data: newData }); 

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