Hi,
https://github.com/dbelikov/Mini-MVP
Introduction
The main goal for Mini-MVP (Model View Presenter) library is to
clearly separate your models from business logic and UI representation
while maintaining their relationships in a concise and well-defined
manner.
Let's say you have some data model that you'd like to use.
(def my-model (mvp/create { :type Text :hint "Enter your age" :value
"1234" :error "Value too big to be true" }))
You define a control that will render the text from the model. I'm
using jQuery here, the sample also demonstrates Closure.
;; Defines a subscriber that will update control's value if the model
changes.
(mvp/add-reader text-model [:text] #(.val (jq "#text2") (:new-value
%)))
;; In a similar way, we also render the error message
(mvp/add-reader my-model [:error] #(.html (jq "#error-message") (:new-
value %)))
;; let's update the error message if the age exceeds 120
(mvp/add-writer my-model [:value]
#(if (> (:new-value %) 120)
(mvp/assoc-value my-model [:error] "Value too big
to be true")
(mvp/assoc-value my-model [:error] "")))
;; finally, update the model when the age is changed
(.change (jq "#input-control") #(mvp/assoc-value my-model [:value] (.
(jq "#input-control") (val))))
Now, if you enter any age less than 120, the error message is cleared.
Enter more than 120 and it'll show up again.
API
create <some clojure data model> <optional initial version> <optional
function to suggest the next version given the current>
Creates a new MVP model
create-ref <existing MVP mode> <path in the model>
Creates a model that references a subpath in the parent model
get-version <MVP model>
Answers the current version of the model. Each change causes
version change.
Assigning equal values is a no-op that doesn't cause version
change.
get-value <MVP model> [path] <optional default value>
Similar to clojure.core/get-in, gets the value in the model
under the specified path.
Empty path fetches the root of the model.
update-value <MVP model> [path] <function to apply> <additional
arguments to the function ...>
Similar to clojure.core/update-in, updates the model's value
under the specified path. The specified function is invoked to get the
new value.
Producing equal value will be considered a no-op.
assoc-value <MVP model> [path] <new-value>
Similar to clojure.core/assoc-in, associates a new value with
the sub-model at the specified path.
Producing equal value will be considered a no-op.
add-writer <MVP model> [path] <subscriber function>
Adds a 1st phase function that will be invoked if the value
under the specified path changes.
The function is not invoked if the change(s) didn't cause value
change.
I.e. given a model { :first "CA" :second "NY" } which is being
updated to { :first "WA" :second "NY" },
the subscriber for :second isn't invoked. The subscribers for
[] and [:first] are to be called.
add-reader <MVP model> [path] <subscriber function>
Exactly the same as add-writer, but these folks are invoked
after all writers.
The idea is to avoid unnecessary UI rendering/flickering while
validators/statistics get updated.
clear <MVP model> [path]
Eliminates all subscribers under the specified path.
delay-events <MVP model> <function>
All subscriber calls are delayed until after the function
completes.
Only subscribers which guarded value has changed will be
called.
I.e. given a subscriber for path=[1] in a model ["a" "b" "c"],
three subsequent changes within (delay-events ...)
["a" "b" "c"] -> ["b" "c" "d"] -> ["e" "f" "g"] -> ["h" "b"
"e"] won't trigger the subscriber.
version <MVP model>
Returns the current version of the model. By default, a new
unique identifier is generated after each actual change.
You can define the initial version and a function to generate
new versions:
(mvp/create {...my data...} 12 inc) ;; will start with
version=12, which is incremented upon each change
License
Same as Clojure/ClojureScript.
Cheers,
Dima
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