Explain why componentDidMount is a better place to make an ajax request

In the docs, in componentWillMount section section it says:

Avoid introducing any side-effects or subscriptions in this method

And in the componentDidMount section:

If you need to load data from a remote endpoint, this is a good place to instantiate the network request

Which for me is confusing because I won't like to wait for the component to be mounted to dispatch an ajax call to fulfill the component data dependencies. I would like to do it as soon as possible, like in the constructor, not even in componentWillMount.

Clearly you may have a reason why you say this in the docs, I might be not seeing the bigger picture. So it will be nice if you can explain a bit more in detail or point me in the direction of where I can find the reason.

React ドキュメントの componentWillMount と componentDidMount に関するリンク先のセクションを、周辺のライフサイクルに関するガイダンスと併せて読んでください。ドキュメントがリモートリクエストを componentDidMount で開始することを推奨している理由を明確にし、マウントまで待つことへの懸念を扱ってください。タイミングに関するガイダンスとその根拠が明確になれば、issue は完了です。