简述 在某些情况下,React框架出于性能优化考虑,可能会将多次state更新合并成一次更新。正因为如此,setState实际上是一个异步的函数。 但是,有一些行为也会阻止React框架本身对于多次state更新的合并,从而让state的更新变得同步化。 比如: eventListeners, Ajax, setTimeout 等等。 详解 当setState() 函数执行的时候,函...
@aweary from other perspective setState is usually synchronous (at least in 16.2) when used in usual react lifecycle (from componentWillReceiveProps). Since it is may be asynchronous in react docs I would say synchronous implementation is better. Author ericgio commented Apr 9, 2018 • edited...
For quite a while I've tried to understood why setState is asynchronous. And failing to find an answer to it in the past, I came to the conclusion that it was for historical reasons and probably hard to change now. However @gaearon indic...
In case you don't have several synchronous state updates, as in your situation, there won't be any issue. This is because the state will update almost instantly after a click, before the system can process another click. Therefore, your... handleClick() { this.setState({isToggleOn: thi...
SetStatehas caused a lot of confusion for newcomers to the React community. A quick search on StackOverflow using the keywords “react setstate” shows there’sstill hazinessabout whethersetStateis asynchronous or synchronous. Eric Elliot even suggestedavoiding setState all togetherand just letting ...
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That almost works -- if using synchronous React (ReactDOM.render) and the state change comes from outside React (e.g. something that runs after an await, or other non-React events), you will get the callback invoked with the old value, not the new one, because React will update ...