The RecordsetFilter plugin provides the ability to filter records within a specific Recordset instance.
State | Population | Land Area |
---|
The filter plugin allows operations to filter a Recordset instance. All the methods generate new Recordsets that are subsets of the original Recordset.
Using the Plugin
The RecordsetFilter plugin supports filtering a Recordset instance using a custom filter function, or key/value pairs.
YUI().use("recordset-base", "recordset-filter", function(Y) { var state_census_data = [ {ANSI: "01000", STATE: "ALABAMA", TOTAL_POP: 4708708, LAND_AREA: 50744, POP_PER_SQ_MILE: 87.6}, {ANSI: "06000", STATE: "CALIFORNIA", TOTAL_POP: 36961664, LAND_AREA: 155959.34, POP_PER_SQ_MILE: 217.2}, {ANSI: "10000", STATE: "DELAWARE", TOTAL_POP: 885122, LAND_AREA: 1953.56, POP_PER_SQ_MILE: 401} ], //instantiate a new Recordset recordset = new Y.Recordset({records: state_census_data}); //Plug it with the Filter plugin recordset.plug(Y.Plugin.RecordsetFilter); //call filter methods with the 'filter' namespace var subset = recordset.filter.filter("STATE", "CALIFORNIA"); });
Filtering by Key/Value
The filter() method can take a key as its first argument, and a value as its second. Doing so will return a subset of the original Recordset, with records that match the specific key/value pair.
//call filter methods with the 'filter' namespace var subset = recordset.filter.filter("STATE", "CALIFORNIA");
Filtering by Custom Function
Additionally, a custom function can be passed in to the filter method. In this scenario, all records will be evaluated against this function, and if a truthy value is returned, it will be pushed onto the returning sub-Recordset.
var myCustomFilterFunction = function(item) { var letter = item.getValue('STATE').charAt(0); if (letter === 'M' || letter === 'N' || letter === 'O' || letter === 'P') { return true; } else { return false; } }; //All records which have a STATE property starting with "M", "N", "O", or "P" will be pushed onto the new Recordset. var subset = recordset.filter.filter(myCustomFilterFunction);
Other Ways to Filter
As Recordset augments Y.Arraylist
, methods from the array-extras
sub-module can be used. Currently, the RecordsetFilter
plugin supports reject()
and grep()
. However, using other methods from the array-extras
utility is straight-forward:
//use the 'array-extras' submodule YUI().use("recordset-base", "recordset-filter", "array-extras", function(Y) { var state_census_data = [ {ANSI: "01000", STATE: "ALABAMA", TOTAL_POP: 4708708, LAND_AREA: 50744, POP_PER_SQ_MILE: 87.6}, {ANSI: "06000", STATE: "CALIFORNIA", TOTAL_POP: 36961664, LAND_AREA: 155959.34, POP_PER_SQ_MILE: 217.2}, {ANSI: "10000", STATE: "DELAWARE", TOTAL_POP: 885122, LAND_AREA: 1953.56, POP_PER_SQ_MILE: 401} ], //instantiate a new Recordset recordset = new Y.Recordset({records: state_census_data}); //Define a custom function customFindFunction = function() { ... } //Use the Array.find method found in the array-extras sub-module var subset = new Y.Recordset({ records: Y.Array.find(recordset.get('records'), customFindFunction) }); });