Several relevant pointers: - https://github.com/facebook/react/issues/7671 https://github.com/facebook/react/issues/7671 - https://twitter.com/dan_abramov/sta

Several relevant pointers: - https://github.com/facebook/react/issues/7671 https://github.com/facebook/react/issues/7671 - https://twitter.com/dan_abramov/status/790590733468241920 https://twitter.com/dan_abramov/status/790590733468241920 - https://www.reddit.com/r/reactjs/comments/5fg7iq/why_should_ajax_requests_go_in_componentdidmount/ https://www.reddit.com/r/reactjs/comments/5fg7iq/why_should_... - https://daveceddia.com/where-fetch-data-componentwillmount-vs-componentdidmount/ https://daveceddia.com/where-fetch-data-componentwillmount-v... Also see Lin Clark's "React Fiber" talk, linked upthread. Basically, pieces of work can start and be interrupted, and then be restarted, which will mean that `componentWillMount` can be called several times before the component _actually_ mounts.