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Improve wording in FAQ entry

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Mike Thompson 2017-10-10 23:58:45 +11:00
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docs/FAQs/PollADatabaseEvery60.md
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### Question ### Question
When the user switches to a certain panel, I'd like to start regularly polling my When the user switches to a particular panel, I'd like to start regularly polling my
backend (database) - say every 60 seconds. And, then later, when the user switches backend (database) - say every 60 seconds. And, then later, when the user switches
away from that panel, I want to stop that polling. away from that panel, I want to stop that polling.
### First, An Architectural Note ### First, An Architectural Note
The broader React community sometimes likes to collocate queries with view components The broader React community often uses a "load data on mount" approach.
and initiate those queries (via a GET?) within the View's `componentDidMount`. They collocate queries with view components
And then, perhaps cleanup/stop any database polling in the Component's `componentWillUnmount`. and initiate these queries (via a GET?) within the View's `componentDidMount` lifecycle method.
And then, later, they might cleanup/stop any database polling in `componentWillUnmount`.
This approach is not idiomatic for re-frame. Views are not imperative This arrangement is not idiomatic for re-frame. Views are not imperative and
(they don't issue database queries), they simply render current application state. they don't initiate database queries. Instead, views simply render current application state.
[Read more in PurelyFunctional.tv's writeup](https://purelyfunctional.tv/article/react-vs-re-frame/) [Read more in PurelyFunctional.tv's writeup](https://purelyfunctional.tv/article/react-vs-re-frame/)
With re-frame, "imperative stuff" only ever happens With re-frame, "imperative stuff" only ever happens
because of an `event`. When the user clicks on a panel-changing widget (a button or a tab?), because an `event` is dispatched. When the user clicks on a panel-changing widget
an event is dispatched, and it is the event handler for this event which knows (perhaps a button or a tab?),
that actions X, Y and Z needs to happen. X might be change application state so an event is dispatched, and it is the event handler associated with this event which
that the view displayed changes, and Y might be change application state so that a computes the effects of the user's action. First, it might change application state so
"twirly thing" is shown over the top, and Z might be to issue a database query. the panel is shown, and then it might further change application state so that a
"twirly busy" thing is shown and, finally, it might issue a database query.
So, having got that issue out the way ... So, having got that issue out the way ...
### Answer ### An Answer
We'll create an effect. It will be general in nature. We'll create an effect. It will be general in nature.