Comment by Bob Cardenas on "Why is it a bad idea to call setState() immediately after componentDidMount in React?"

The official documentation site for React recommends multiple times that ajax and subsequent setState calls should be done in componentDidMount. I can find no other reliable source that suggests this is a bad practice. Although I understand the rationale for making the ajax call earlier in the lifecycle (e.g., using componentWillMount), I'm curious why the official React site recommends using componentDidMount. Are there potential issues with using componentWillMount instead of componentDidMount?

References facebook.github.io/react/docs/component-specs.html, facebook.github.io/react/docs/tutorial.html, and facebook.github.io/react/tips/initial-ajax.html).

About the componentWillMount ...

"There is talk about removing componentWillMount from class components since it serves the same purpose as the constructor. It will remain on createClass components. " -- stackoverflow.com/a/27139507/491181

About componentDidMount ..

" when you change the route for the same view, with a different parameter in path (ie from "/user/42" to "/user/14166"), the same view will be used, with the same root DOM, and componentDidMount WILL NOT be triggered " --disq.us/p/1duw14v

"certainly, and i'd say componentwillreceiveprops() seems more adequate. But it's a LOT more boilerplate & bug prone (IMHO) using the components lifecycle. You'll have to check which properties have changed. " -- disq.us/p/1h8g1bz

Calling an Ajax method (and THEN calling setState when it completes) is not the same thing as calling setState directly in componentDidMount.

The gist of the initial advice is don't call setState in componentDidMount. Kicking off an async process (ajax call) that calls setState will do it AFTER componentDidMount has finished (and should therefore trigger componentDidUpdate, rather than forceUpdate.

Yes? medium.com/@baphemot/understanding-reactjs-compon…

cause side effects (AJAX calls etc.)

DON’T

call this.setState as it will result in a re-render

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