javascript ImmutableJS - 更新列表中的值
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ImmutableJS - update value in a List
提问by user3696212
I have a Map like this (in ImmutableJS):
我有一个这样的地图（在 ImmutableJS 中）：
{arrayOfValues: [
{one: {inside: 'first in array'}},
{one: {inside: 'second in array'}}
]}
And I want to update the value "inside" in the second entry in the "arrayOfValues" array. How can I do it? This is what I have now and it says "Uncaught Error: invalid keyPath"
我想更新“arrayOfValues”数组中第二个条目中的“inside”值。我该怎么做？这就是我现在所拥有的，它说“未捕获的错误：无效的keyPath”
theMap.update('arrayOfValues',(list)=>{
return list.setIn([1,'one','inside'],'updated value');
})
I also tried directly this and it didn't work:
我也直接尝试过这个，但没有用：
theMap.setIn(['arrayOfValues',1,'one','inside'],'updated value');
After several hours of looking for the solution, I appreciate any help. Thank you.
经过几个小时的寻找解决方案，我感谢任何帮助。谢谢你。
回答by Brian Park
What you are doing is correct (see this JSBin).
你在做什么是正确的（见这个JSBin）。
const orig = Immutable.fromJS({
arrayOfValues: [
{ one: { inside: 'first in array' } },
{ one: { inside: 'second in array' } },
]
});
const updated = orig.setIn(['arrayOfValues', 1, 'one', 'inside'], 'updated value');
console.log(updated.toJS());
// {
// arrayOfValues: [
// { one: { inside: 'first in array' } },
// { one: { inside: 'second in array' } },
// ]
// }
When you call orig.setIn(), it doesn't modify origdirectly. That's the whole purpose of this Immutablelibrary. It doesn't mutate the existing data but creates a new one from the existing one.
当您调用 时orig.setIn()，它不会orig直接修改。这就是这个Immutable图书馆的全部目的。它不会改变现有数据，而是从现有数据创建一个新数据。
回答by Brian Kent
Your setInexample works as you should see in this plunkr:
http://plnkr.co/edit/1uXTWtKlykeuU6vB3xVO?p=preview
您的setIn示例如您在此 plunkr 中看到的那样工作：http://plnkr.co/edit/1uXTWtKlykeuU6vB3xVO?p=preview
Perhaps you are assuming the value of theMapwill be changed as a result of the setIn?
也许您假设 的值theMap将因setIn?
As these structures are immutable, you must capture the modified value in a new variable as var theMap2 = theMap.setIn(['arrayOfValues',1,'one','inside'],'updated value');
由于这些结构是不可变的，因此您必须在新变量中捕获修改后的值，如 var theMap2 = theMap.setIn(['arrayOfValues',1,'one','inside'],'updated value');
回答by Tauqeer Hassan
activePane is the index of Object in Array(List) that I had to modify
activePane 是我必须修改的 Array(List) 中对象的索引
case CHANGE_SERVICE:
var obj = {
title: '1212121 Tab',
service: '',
tagName: '',
preDefinedApi: '',
methodType: '',
url: '',
urlParams: [{
label: '',
name: '',
value: '',
}],
headers: [{
label: '',
name: '',
value: '',
}],
};
var activePane = state.get('activePane');
var panes = state.setIn(['panes', activePane, 'service'], action.val);
return state.setIn(['panes', activePane, 'service'], action.val);
