Knockout.js 有类似 AngularJS 的过滤器吗？
Is there something like AngularJS' filters for Knockout.js?
angularjs has the angular-filters 内置概念，因此很容易将数据集缩减为与用户输入匹配的元素。
knockout.js 有类似的东西吗？
当然我可以自己实现它，使用普通的旧 Javascript，但我不是性能专家所以我自己的解决方案可能会非常慢。
我认为您正在寻找如下函数：ko.utils.arrayMap ko.utils.arrayForEach ko.utils.arrayFilter ko.utils.arrayFirst
您可以在 http://www.knockmeout.net/2011/04/utility-functions-in-knockoutjs.html
找到这些以及更多内容
对你有帮助吗？
是的，Steve Sanderson has created the knockout-projections 用于淘汰赛的插件。
这类似于 angular-filters，您可以在其中将映射或过滤器应用于源集合以生成另一个集合供您绑定到 UI。
项目 github 自述文件 中的这个示例演示了用法并解释了 map 和 filter 回调如何有效执行：
Mapping
More info to follow. For now, here's a simple example:
var sourceItems = ko.observableArray([1, 2, 3, 4, 5]);
There's a plain observable array. Now let's say we want to keep track
of the squares of these values:
var squares = sourceItems.map(function(x) { return x*x; });
Now squares is an observable array containing [1, 4, 9, 16, 25]. Let's modify the source data:
sourceItems.push(6);
// 'squares' has automatically updated and now contains [1, 4, 9, 16, 25, 36]
This works with any transformation of the source data, e.g.:
sourceItems.reverse();
// 'squares' now contains [36, 25, 16, 9, 4, 1]
The key point of this library is that these transformations are done efficiently. Specifically, your callback function that performs
the mapping is only called when strictly necessary (usually, that's
only for newly-added items). When you add new items to the source
data, we don't need to re-map the existing ones. When you reorder
the source data, the output order is correspondingly changed without
remapping anything.
This efficiency might not matter much if you're just squaring numbers,
but when you are mapping complex nested graphs of custom objects, it
can be important to perform each mapping update with the minumum of
work.
Filtering
As well as map, this plugin also provides filter:
var evenSquares = squares.filter(function(x) { return x % 2 === 0; });
// evenSquares is now an observable containing [36, 16, 4]
sourceItems.push(9);
// This has no effect on evenSquares, because 9*9=81 is odd
sourceItems.push(10);
// evenSquares now contains [36, 16, 4, 100]
Again, your filter callbacks are only called when strictly
necessary. Re-ordering or deleting source items don't require any
refiltering - the output is simply updated to match. Only newly-added
source items must be subjected to your filter callback.
angularjs has the angular-filters 内置概念，因此很容易将数据集缩减为与用户输入匹配的元素。
knockout.js 有类似的东西吗？
当然我可以自己实现它，使用普通的旧 Javascript，但我不是性能专家所以我自己的解决方案可能会非常慢。
我认为您正在寻找如下函数：ko.utils.arrayMap ko.utils.arrayForEach ko.utils.arrayFilter ko.utils.arrayFirst
您可以在 http://www.knockmeout.net/2011/04/utility-functions-in-knockoutjs.html
找到这些以及更多内容对你有帮助吗？
是的，Steve Sanderson has created the knockout-projections 用于淘汰赛的插件。
这类似于 angular-filters，您可以在其中将映射或过滤器应用于源集合以生成另一个集合供您绑定到 UI。
项目 github 自述文件 中的这个示例演示了用法并解释了 map 和 filter 回调如何有效执行：
Mapping
More info to follow. For now, here's a simple example:
var sourceItems = ko.observableArray([1, 2, 3, 4, 5]);There's a plain observable array. Now let's say we want to keep track of the squares of these values:
var squares = sourceItems.map(function(x) { return x*x; });Now
squaresis an observable array containing[1, 4, 9, 16, 25]. Let's modify the source data:sourceItems.push(6); // 'squares' has automatically updated and now contains [1, 4, 9, 16, 25, 36]This works with any transformation of the source data, e.g.:
sourceItems.reverse(); // 'squares' now contains [36, 25, 16, 9, 4, 1]The key point of this library is that these transformations are done efficiently. Specifically, your callback function that performs the mapping is only called when strictly necessary (usually, that's only for newly-added items). When you add new items to the source data, we don't need to re-map the existing ones. When you reorder the source data, the output order is correspondingly changed without remapping anything.
This efficiency might not matter much if you're just squaring numbers, but when you are mapping complex nested graphs of custom objects, it can be important to perform each mapping update with the minumum of work.
Filtering
As well as
map, this plugin also providesfilter:var evenSquares = squares.filter(function(x) { return x % 2 === 0; }); // evenSquares is now an observable containing [36, 16, 4] sourceItems.push(9); // This has no effect on evenSquares, because 9*9=81 is odd sourceItems.push(10); // evenSquares now contains [36, 16, 4, 100]Again, your
filtercallbacks are only called when strictly necessary. Re-ordering or deleting source items don't require any refiltering - the output is simply updated to match. Only newly-added source items must be subjected to yourfiltercallback.