Plugins/sorting/absolute.js

/**
 * When sorting a DataTable you might find that you want to keep a specific
 * item at the top or bottom of the table. For example when sorting a column
 * of numbers, if a value is `null` or `N/A` you might want to keep it at the
 * bottom of the table, regardless of if ascending or descending sorting is
 * applied. This plug-in provides that ability.
 *
 * You must call the `$.fn.dataTable.absoluteOrder` with information about the
 * value(s) you wish to make absolute in the sorting order and store the
 * returned value, assigning it to the `columns.type` option for the column
 * you wish this sorting to be applied to.
 *
 * For number based columns a `$.fn.dataTable.absoluteOrderNumber` function is
 * also available.
 *
 * @name Absolute sorting
 * @summary Keep one or more items at the top and/or bottom of a table when sorting
 * @author [Allan Jardine](//datatables.net)
 * @depends DataTables 1.10+
 *
 * @example
 *    var namesType = $.fn.dataTable.absoluteOrder( [
 *      { value: '', position: 'top' }
 *    ] );
 *    
 *    var numbersType = $.fn.dataTable.absoluteOrderNumber( [
 *      { value: 'N/A', position: 'bottom' }
 *    ] );
 *    
 *    $('#example').DataTable( {
 *      columnDefs: [
 *        { type: namesType, targets: 0 },
 *        { type: numbersType, targets: 1 }
 *      ]
 *    } );
 */

(function( factory ){
	if ( typeof define === 'function' && define.amd ) {
		// AMD
		define( ['jquery', 'datatables.net'], function ( $ ) {
			return factory( $, window, document );
		} );
	}
	else if ( typeof exports === 'object' ) {
		// CommonJS
		module.exports = function (root, $) {
			if ( ! root ) {
				root = window;
			}

			if ( ! $ || ! $.fn.dataTable ) {
				$ = require('datatables.net')(root, $).$;
			}

			return factory( $, root, root.document );
		};
	}
	else {
		// Browser
		factory( jQuery, window, document );
	}
}(function( $, window, document, undefined ) {
'use strict';

// Unique value allowing multiple absolute ordering use cases on a single page.
var _unique = 0;

// Function to encapsulate code that is common to both the string and number
// ordering plug-ins.
var _setup = function ( values ) {
	if ( ! $.isArray( values ) ) {
		values = [ values ];
	}

	var o = {
		name: 'absoluteOrder'+(_unique++),
		alwaysTop: {},
		alwaysBottom: {}
	};

	// In order to provide performance, the symbols that are to be looked for
	// are stored as parameter keys in an object, allowing O(1) lookup, rather
	// than O(n) if it were in an array.
	for ( var i=0, ien=values.length ; i<ien ; i++ ) {
		var conf = values[i];

		if ( typeof conf === 'string' ) {
			o.alwaysTop[ conf ] = true;
		}
		else if ( conf.position === undefined || conf.position === 'top' ) {
			o.alwaysTop[ conf.value ] = true;
		}
		else {
			o.alwaysBottom[ conf.value ] = true;
		}
	}

	// Ascending ordering method
	o.asc = function ( a, b, isNumber ) {
		if ( o.alwaysTop[ a ] || o.alwaysBottom[ b ] ) {
			return -1;
		}
		else if ( o.alwaysBottom[ a ] || o.alwaysTop[ b ] ) {
			return 1;
		}

		if ( isNumber ) {
			// Cast as a number if required
			if ( typeof a === 'string' ) {
				a = a.replace(/[^\d\-\.]/g, '') * 1;
			}
			if ( typeof b === 'string' ) {
				b = b.replace(/[^\d\-\.]/g, '') * 1;
			}
		}

		return ((a < b) ? -1 : ((a > b) ? 1 : 0));
	};

	// Descending ordering method
	o.desc = function ( a, b, isNumber ) {
		if ( o.alwaysTop[ a ] || o.alwaysBottom[ b ] ) {
			return -1;
		}
		else if ( o.alwaysBottom[ a ] || o.alwaysTop[ b ] ) {
			return 1;
		}

		if ( isNumber ) {
			if ( typeof a === 'string' ) {
				a = a.replace(/[^\d\-\.]/g, '') * 1;
			}
			if ( typeof b === 'string' ) {
				b = b.replace(/[^\d\-\.]/g, '') * 1;
			}
		}

		return ((a < b) ? 1 : ((a > b) ? -1 : 0));
	};

	return o;
};

// String based ordering
$.fn.dataTable.absoluteOrder = function ( values ) {
	var conf = _setup( values );

	$.fn.dataTable.ext.type.order[ conf.name+'-asc' ] = conf.asc;
	$.fn.dataTable.ext.type.order[ conf.name+'-desc' ] = conf.desc;

	// Return the name of the sorting plug-in that was created so it can be used
	// with the `columns.type` parameter. There is no auto-detection here.
	return conf.name;
};

// Number based ordering - strips out everything but the number information
$.fn.dataTable.absoluteOrderNumber = function ( values ) {
	var conf = _setup( values );

	$.fn.dataTable.ext.type.order[ conf.name+'-asc' ] = function ( a, b ) {
		return conf.asc( a, b, true );
	};
	$.fn.dataTable.ext.type.order[ conf.name+'-desc' ] = function ( a, b ) {
		return conf.desc( a, b, true );
	};

	return conf.name;
};


}));