File: arraysort/js/arraysort.js

            /*jshint expr:true, onevar:false */
            
            /**
            Provides comparator functions useful for sorting arrays.
            
            @module arraysort
            **/
            
            var LANG = Y.Lang,
                ISVALUE = LANG.isValue,
                ISSTRING = LANG.isString;
            
            /**
            Provides comparator functions useful for sorting arrays.
            
            @class ArraySort
            @static
            **/
            
            var ArraySort = Y.ArraySort = {
                // -- Public Methods -------------------------------------------------------
            
                /**
                Comparator function for simple case-insensitive sorting of an array of
                strings.
            
                @method compare
                @param a {Object} First sort argument.
                @param b {Object} Second sort argument.
                @param desc {Boolean} `true` if sort direction is descending, `false` if
                    sort direction is ascending.
                @return {Boolean} -1 when a < b. 0 when a == b. 1 when a > b.
                @static
                */
                compare: function(a, b, desc) {
                    if(!ISVALUE(a)) {
                        if(!ISVALUE(b)) {
                            return 0;
                        }
                        else {
                            return 1;
                        }
                    }
                    else if(!ISVALUE(b)) {
                        return -1;
                    }
            
                    if(ISSTRING(a)) {
                        a = a.toLowerCase();
                    }
                    if(ISSTRING(b)) {
                        b = b.toLowerCase();
                    }
                    if(a < b) {
                        return (desc) ? 1 : -1;
                    }
                    else if (a > b) {
                        return (desc) ? -1 : 1;
                    }
                    else {
                        return 0;
                    }
                },
            
                /**
                Performs a natural-order comparison of two strings or numbers (or a string
                and a number). This ensures that a value like 'foo2' will be sorted before
                'foo10', whereas a standard ASCII sort would sort 'foo10' first.
            
                @example
            
                    var items = ['item10', 'item2', 'item1', 10, '1', 2];
            
                    items.sort(Y.ArraySort.naturalCompare);
                    console.log(items); // => ['1', 2, 10, 'item1', 'item2', 'item10']
            
                @method naturalCompare
                @param {Number|String} a First value to compare.
                @param {Number|String} b Second value to compare.
                @param {Object} [options] Options.
                    @param {Boolean} [options.caseSensitive=false] If `true`, a
                        case-sensitive comparison will be performed. By default the
                        comparison is case-insensitive.
                    @param {Boolean} [options.descending=false] If `true`, the sort order
                        will be reversed so that larger values are sorted before smaller
                        values.
                @return {Number} `0` if the two items are equal, a negative number if _a_
                    should be sorted before _b_, or a positive number if _b_ should be
                    sorted before _a_.
                @static
                @since 3.11.0
                **/
                naturalCompare: function (a, b, options) {
                    // Coerce `a` and `b` to strings.
                    a += '';
                    b += '';
            
                    // Convert `a` and `b` to lowercase unless `options.caseSensitive` is
                    // truthy.
                    if (!options || !options.caseSensitive) {
                        a = a.toLowerCase();
                        b = b.toLowerCase();
                    }
            
                    // Split `a` and `b` into alpha parts and numeric parts.
                    var aParts = ArraySort._splitAlphaNum(a),
                        bParts = ArraySort._splitAlphaNum(b),
                        length = Math.min(aParts.length, bParts.length),
                        result = 0,
            
                        aPart,
                        bPart,
                        i;
            
                    // Compare each part of `a` with each part of `b`.
                    for (i = 0; i < length; i++) {
                        aPart = aParts[i];
                        bPart = bParts[i];
            
                        // If the two parts aren't equal, compare them and stop iterating.
                        if (aPart !== bPart) {
                            // First, try comparing them as numbers.
                            result = aPart - bPart;
            
                            // If that didn't work, compare them as strings. This falsiness
                            // check works because `result` can't be 0 (we checked for
                            // equality above) and NaN is falsy.
                            if (!result) {
                                result = aPart > bPart ? 1 : -1;
                            }
            
                            // At this point we know enough to be able to sort the two
                            // strings, so we don't need to compare any more parts.
                            break;
                        }
                    }
            
                    // If we get here and `result` is still 0, then sort the shorter string
                    // before the longer string.
                    result || (result = a.length - b.length);
            
                    // Return the result, flipping the order if `options.descending` is
                    // truthy.
                    return options && options.descending ? -result : result;
                },
            
                // -- Protected Methods ----------------------------------------------------
            
                /**
                Splits a string into an array of alpha character and digit character parts.
            
                @example
            
                    Y.ArraySort._splitAlphaNum('abc123def456');
                    // => ['abc', '123', 'def', '456']
            
                @method _splitAlphaNum
                @param {String} string String to split.
                @return {String[]} Array of alpha parts and digit parts.
                @protected
                @static
                @since 3.11.0
                **/
                _splitAlphaNum: function (string) {
                    /*jshint boss:true */
                    var parts = [],
                        regex = /(\d+|\D+)/g,
                        match;
            
                    while (match = regex.exec(string)) { // assignment
                        parts.push(match[1]);
                    }
            
                    return parts;
                }
            };