我知道，React教程和文档毫无疑问地警告说，状态不应该直接变异，所有事情都应该通过setState。

我想了解一下，为什么我不能直接更改状态，然后（在同一函数中）调用this.setState({})仅触发render。

例如：以下代码似乎正常工作：

const React = require('react');

const App = React.createClass({
    getInitialState: function() {
        return {
            some: {
                rather: {
                    deeply: {
                        embedded: {
                            stuff: 1
                        }}}}};
    },
    updateCounter: function () {
        this.state.some.rather.deeply.embedded.stuff++;
        this.setState({}); // just to trigger the render ...
    },
    render: function() {
        return (
                <div>
                Counter value: {this.state.some.rather.deeply.embedded.stuff}
                <br></br>
                <button onClick={this.updateCounter}>inc</button>
                </div>
        );
    }
});

export default App;

I am all for following conventions but I would like to enhance my further understanding of how ReactJS actually works and what can go wrong or is it sub-optimal with the above code.

The notes under the this.setState documentation basically identify two gotchas:

1. That if you mutate state directly and then subsequently call this.setState this may replace (overwrite?) the mutation you made. I don't see how this can happen in the above code.
2. That setState may mutate this.state effectively in an asynchronous / deferred way and so when accessing this.state right after calling this.setState you are not guaranteed to access the final mutated state. I get that, by this is not an issue if this.setState is the last call of the update function.