Allow action handler to abort multi-select, resetting last index state #918
Conversation
ahmacleod
requested review from
bantic,
twokul,
c69-addepar,
kpfefferle and
mixonic
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| There is, however, some internal state that needs to be reset to fully abort a user selection. For example, Ember Table tracks the _last selected_ row in order to determine the range of rows affected in a user multi-selection. If the intent is to completely prevent a user selection, this value must not change when the action is aborted. Otherwise, a subsequent user multi-selection may target the wrong rows. | ||
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| To reset all internal state relating to an attempted user selection, call the `abort` function in the options object passed to the `onChange` action handler: |
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why cannot we automatically perform the cleanup ? 🤔 ( i believe there are reasons, but i'm just not able to figure out from the code )
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I think from Ember Table's perspective, there's no reason to perform any cleanup at all. Selection is purely DDAU, so ET can't infer very much when it receives a new selection attr. The notion of a forbidden or cancelled selection is something we've made up in the application layer.
My intent with this PR was to provide what's needed to implement this logic in the application, but not force it on anyone, or change how existing applications use the onSelect action. I've kept the abort handler rather vague in its description so that we can tweak exactly what it does in the future.
…bort-multi-select
Description
Adds ability to "abort" a selection, resetting the internally-tracked last selected row index. This allows multi-select to function as expected after rejecting a user's selection.
Use case
Say we want to prevent the user from selecting more than 10 rows.
If the user clicks row 1 and then shift-clicks row 11, we can inspect the proposed new selection in the
onSelectaction, determine it is too large, and show an error without making a change.However, if they subsequently shift-click row 5, Ember Table will attempt to add rows 5-11 to the selection, as row 11 was the last clicked.
By calling
abort(), the internal state is reverted, and shift-clicking row 5 will select rows 1-5.Docs Update