status-im
/
re-frame
mirror of https://github.com/status-im/re-frame.git
2
0
Fork 0
Code Issues Projects Releases Wiki Activity

Tweak subscription documentation

This commit is contained in:
Mike Thompson 2017-07-14 13:56:39 +10:00
parent 31ba95ba1b
commit db1496bfe3
1 changed files with 15 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
docs/SubscriptionsCleanup.md
View File

@ -71,7 +71,7 @@ Above, I suggested this:
@(rf/subscribe [:time-str])])
```
But that may offend your aesthetics. Too much noise with those `@`?
But that may offend your aesthetics. Too much noise with those two `@`?
To clean this up, we can define a new `listen` function:
```clj
@ -91,6 +91,16 @@ And then rewrite:
So, at the cost of writing your own function, `listen`, the code is now less noisy
AND there's less chance of us forgetting an `@` (which can lead to odd problems).
### LambdaIsland Naming (LIN)
I've ended up quite liking [the alternative names](https://lambdaisland.com/blog/11-02-2017-re-frame-form-1-subscriptions)
suggested by [Lambda Island Videos](https://lambdaisland.com/):
```cljs
(def <sub (comp deref re-frame.core/subscribe)) ;; aka listen (above)
(def >evt re-frame.core/dispatch)
```
### Say It Again
So, if, in code review, you saw this view function:
@ -102,8 +112,8 @@ So, if, in code review, you saw this view function:
```
What would you (supportively) object to?
That `sort`, right? Computation in the view. Instead, we want the right data
delivered to the view - its job is to simply make `hiccup`.
That `sort`, right? Computation in the view. Instead, we want exactly the right data
delivered to the view - no further computation required - the view's job is to simply make `hiccup`.
The solution is to create a subscription that delivers items already sorted.
```clj
@ -134,15 +144,14 @@ Now it is easy to test `item-sorter` independently.
### And There's Another Benefit
re-frame de-duplicates signal graph nodes.
re-frame de-duplicates signal graph nodes.
If, for example, two views wanted to `(subscribe [:sorted-items])` only the one node
(in the signal graph) would be created. Only one node would be doing that
potentially expensive sorting operation (when items changed) and values from
it would be flowing through to both views.
That sort of efficiency can't happen if this views themselves are doing the `sort`.
That sort of efficiency can't happen if this views themselves are doing the `sort`.
### de-duplication