Rxjs 观察对象更新和变化 [英] Rxjs observing object updates and changes
问题描述
我目前正在尝试观察给定对象的任何更改,包括它的所有元素.
I am currently trying to observe any changes to a given object including all of it's elements.
以下代码仅在更新 object[x] 时触发,但不会在单独更新 object[x] 的元素(例如 object[x][y])时触发
The following code only fires when an object[x] is updates, but not if individually updating object[x]'s elements such as object[x][y]
<script>
var elem = document.getElementById("test1");
var log = function(x) {
elem.innerHTML += x + "<br/><br/><br/>";
};
var a = [{a:1,b:2},
{a:2,b:5}
];
var source = Rx.Observable
.ofObjectChanges(a)
.map(function(x) {
return JSON.stringify(x);
});
var subscription = source.subscribe(
function (x) {log(x);},
function (err) {log(err);},
function () {log('Completed');}
);
a[0] = a[1];
</script>
此代码正确运行并触发.
This code runs and fires correctly.
不过.如果我改为这个
a[0]['a'] = 3;
然后什么都没有发生.
编辑
一个更好的表述方式,我如何观察对象数组的变化?
A better way to phrase this, how can I observe changes from an array of objects?
推荐答案
如果您只想更改嵌套对象:
If you want only the nested object changes:
var source = rx.Observable.from(a).flatMap(function(item) {
return rx.Observable.ofObjectChanges(item);
});
如果您还想要像 a[0] = a[1]
之类的更改:
If you also want changes like a[0] = a[1]
:
var source = rx.Observable.merge(
rx.Observable.ofArrayChanges(a),
rx.Observable.from(a).flatMap(function(item) {
return rx.Observable.ofObjectChanges(item);
})
);
flatMap
或 selectMany
(它们是相同的函数)将允许您迭代一个值并执行一个返回 Observable 的函数.来自所有这些 Observable 的值被扁平化"到返回的新流上.
The flatMap
or selectMany
(they are the same function) will allow you to iterate over a value and execute a function that returns an Observable. The values from all these Observables are "flattened" onto a new stream that is returned.
http://reactivex.io/documentation/operators/flatmap.html
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