OData filter preparator: simple, compact and easy to extend created to resolve the issue of preparing the OData filter presented in these dicussions: - http://stackoverflow.com/questions/19251441/how-to-cast-with-eq-in-odata-filtering - http://stackoverflow.com/questions/19319170/how-to-escape-single-quote-in-odata-filter-uri - http://stackoverf…

odataFilter.js

/*
* OData filter preparator: 
* simple, compact and easy to extend 
* copyright (c) Mohamed Ali Jamaoui 2013
*
*  can be used on the fly to prepare the OData filter 
*  can easly be extended to handle new Edm types 
*   > the list of Edm types can be found here: 
*   > http://www.odata.org/documentation/odata-v2-documentation/overview/#6_Primitive_Data_Types
*   > check the detailed description here: http://intelligea.wordpress.com/2013/10/12/how-to-format-odata-filters-values-on-the-fly-using-their-edm-types/
*/
var odataHandler = {};

odataHandler.odataFilter = function module(){
  
	var filterList = {}; 
	
	//private function for escape special characters in a string 
	//currently escaping in order: single quote, ampersand 
	function escapeString(string){
		string = string.replace(/'/g,'\'\'');
		string = string.replace(/&/g,'%26');
		return string;
	}
	
	function exports(){}
	
	exports.prepareFilter = function(_EdmType, _value){
		return filterList[_EdmType] ? filterList[_EdmType](_value) : "Edm Type unhandled yet";
	};
	
	//add a new filter or overwrites an existing one 
	exports.addFilterHandler = function(_EdmType, _callbackFunction){
		filterList[_EdmType] = _callbackFunction;
		//allow method chaining 
		return this; 
	};
	
	//return the list of the supported EDM types 
	exports.getSupportedEdmTypes = function(){
		return Object.keys(filterList);
	};
	
	//adding default filter handlers; 
	exports.addFilterHandler("Edm.DateTime", function(_value){return "datetime'"+_value+"'";});
	exports.addFilterHandler("Edm.Decimal", function(_value){return _value+"M";});
	exports.addFilterHandler("Edm.Single", function(_value){return _value+"f";});
	exports.addFilterHandler("Edm.Int64", function(_value){return _value+"L";});
	exports.addFilterHandler("Edm.Int32", function(_value){return _value;});
	exports.addFilterHandler("Edm.Int16", function(_value){return _value;});
	//escape single quote if any, ampersand if any and return the string  
	exports.addFilterHandler("Edm.String", function(_value){return "'"+ escapeString(_value)+"'";});
	
	return exports; 
};



//How to use 
var test = odataHandler.odataFilter();

//how to extend with new handler 
test.addFilterHandler("Edm.Int16", function(_value){
	return _value;
});

//how to prepare filter on the fly 
console.log(test.prepareFilter("Edm.DateTime","1996-07-04T00:00:00"));
//result >> datetime'1996-07-04T00:00:00'