ReactJS - ComponentDidMount 在渲染之前执行 [英] ReactJS - ComponentDidMount is executing before render
问题描述
我在反应方面遇到了一些问题.我在渲染时使用 map 函数,并且在完成之前调用了 componentDidMount 函数.
I´m having some problems with react. I´m using map function at render and the function componentDidMount is being called before it finish.
这里是我的代码片段
componentDidMount: function() {
console.info("didMount");
},
render: function() {
return React.createElement("div", null,
this.state.fields.map(function(field) {
console.info("field" + field);
return React.createElement("span", null, field);
}.bind(this)));
}
在field..."之前打印didMount".我该如何解决这个问题?似乎地图是异步的.
It being printed "didMount" before "field...". How can i solve this? It seems that map is async.
谢谢
推荐答案
你如何初始化你的 this.state.fields
?如果您在 componentDidMount
函数中执行此操作,则 console.info("field" + field);
永远不会执行,因为该字段/数组为空.
How are you initializing your this.state.fields
? If you do it in the componentDidMount
function, then console.info("field" + field);
never gets executed because the field/array is null.
使用 setState 回调 参数在状态完成后运行代码初始化/更新.
Use the setState callback parameter to run code after the state has been initialized/updated.
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