javascript - 初学React，setState后获取到的this.state没变，还是初始state？

问题描述

问 题

          getInitialState(){
            return {data:[]};
          },
          componentDidMount(){
            var data = [ { author: "Pete Hunt", text: "This is one comment" },
                         { author: "Jordan Walke", text: "This is *another* comment" } ];
            (function(data){
              this.setState({data:data});
              console.log(this.state.data);
            }).call(this,data);
          },

为什么log里打出来的data是[]呢？

解决方案

善用官方文档：

void setState(
  function|object nextState,
  [function callback]
)

The second (optional) parameter is a callback function that will be executed once setState is completed and the component is re-rendered.

所以正确做法是

this.setState(
    Object.assign({}, { data }),
    () => console.log(this.state)
)

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