freactive items-view ideas

items-view will be a function taking a map of arguments:

(items-view
  {:items items
   :container [:ul]
   :template (fn [item] [:li @item])})

We can do sorting like this:

(def items (observable-vector [{:a 0 :b 2}]))
(items-view
  {:items items
   :container [:ul]
   :template (fn [item] [:li (rx (:a @item))])
   :sort-by sort-by-atom})

where sort-by-atom is some reactive data source (that responds to a user clicking something like column headings for instance) which contains a function that could be passed as the comparator argument to sorted-map-by.

I would propose support for the following keys:

Key	Description
`:items`	an instance of `IObservableCollection` (required) (not bindable)
`:template`	a function that will be used to create the item view for each item should take a single item for the cursor to the item (required) (not bindable)
`:container`	the container in which to bind the items as children (defaults to `[:span]`) (not bindable but can contain attribute bindings)
`:sort-by`	a comparator as would be passed to `sorted-map-by` (defaults to `nil`) (bindable)
`:sort-order`	`:asc` or `:desc` (defaults to `:asc`) (bindable)
`:filter`	a predicate as would be passed to `filter` (bindable)
`:lower-index`	specifies the lowest index (in sort order) to be displayed (using `data.avl`'s `nth`) (bindable)
`:upper-index`	specifies the highest index (in sort order) to be displayed (using `data.avl`'s `nth`) (bindable)
`:lower-test`	a vector `[test key]` where test is `>` or `>=` as would be passed to `subkey` for efficiently setting a lower bound (using `data.avl`) (bindable)
`:upper-test`	a vector `[test key]` where test is `<` or `<=` as would be passed to `subkey` for efficiently setting an upper bound (using `data.avl`) (bindable)
`:header`	a vector of elements to be inserted as the first children of the container before dynamic items (not bindable but can contain bindings)
`:footer`	a vector of elements to be inserted as the last children of the container after dynamic items (not bindable but can contain bindings)
`:placeholder`	a single element or `nil` that can be inserted as a place holder (for things like sorting and drag and drop) when `:placeholder-idx` is not `nil` (bindable)
`:placeholder-idx`	the index where `:placeholder` should be inserted or `nil` (bindable)

Sorting will be provided by data.avl and will need to be explicitly enabled like a plugin (to reduce code size when not needed). Alternatively there could be a simple items view which doesn't support sorting and a more advanced version which does.

An items-view could also potentially work as a plugin to freactive's normal syntax:

[:freactive/items-view
  {:items items
   :container [:ul]
   :template (fn [item] [:li @item])}]

aaronc/freactive-items-view.md

aaronc commented Dec 18, 2014

aaronc commented Dec 18, 2014