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docs(select): clarify policy of track by and select as

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Jeff Cross
2014-10-10 10:24:14 -07:00
parent d71fb6f271
commit ea1897606f
1 changed files with 4 additions and 4 deletions
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8
src/ng/directive/select.js
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@@ -38,15 +38,15 @@ var ngOptionsMinErr = minErr('ngOptions');
* <div class="alert alert-info">
* **Note:** Using `select as` will bind the result of the `select as` expression to the model, but
* the value of the `<select>` and `<option>` html elements will be either the index (for array data sources)
* or property name (for object data sources) of the value within the collection.
* or property name (for object data sources) of the value within the collection.
* </div>
*
* **Note:** Using `select as` together with `trackexpr` is not possible (and will throw an error).
* **Note:** Using `select as` together with `trackexpr` is not recommended.
* Reasoning:
* - Example: &lt;select ng-options="item.subItem as item.label for item in values track by item.id" ng-model="selected"&gt;
* values: [{id: 1, label: 'aLabel', subItem: {name: 'aSubItem'}}, {id: 2, label: 'bLabel', subItem: {name: 'bSubItemß'}}],
* values: [{id: 1, label: 'aLabel', subItem: {name: 'aSubItem'}}, {id: 2, label: 'bLabel', subItem: {name: 'bSubItem'}}],
* $scope.selected = {name: 'aSubItem'};
* - track by is always applied to `value`, with purpose to preserve the selection,
* - track by is always applied to `value`, with the purpose of preserving the selection,
* (to `item` in this case)
* - to calculate whether an item is selected we do the following:
* 1. apply `track by` to the values in the array, e.g.