这是一个“优化”版本。它进行了更多的预处理，并为每个排序选项预先创建了比较功能。它可能需要更多的内存（因为它为每个排序选项存储了一个功能，但是它应该执行得更好一些，因为在比较过程中不必确定正确的设置。尽管如此，我也没有进行任何分析。
var sort_by;(function() { // utility functions var default_cmp = function(a, b) { if (a == b) return 0; return a < b ? -1 : 1; }, getCmpFunc = function(primer, reverse) { var dfc = default_cmp, // closer in scope cmp = default_cmp; if (primer) { cmp = function(a, b) { return dfc(primer(a), primer(b)); }; } if (reverse) { return function(a, b) { return -1 * cmp(a, b); }; } return cmp; }; // actual implementation sort_by = function() { var fields = [], n_fields = arguments.length, field, name, reverse, cmp; // preprocess sorting options for (var i = 0; i < n_fields; i++) { field = arguments[i]; if (typeof field === 'string') { name = field; cmp = default_cmp; } else { name = field.name; cmp = getCmpFunc(field.primer, field.reverse); } fields.push({ name: name, cmp: cmp }); } // final comparison function return function(A, B) { var a, b, name, result; for (var i = 0; i < n_fields; i++) { result = 0; field = fields[i]; name = field.name; result = field.cmp(A[name], B[name]); if (result !== 0) break; } return result; } }}());用法示例：
homes.sort(sort_by('city', {name:'price', primer: parseInt, reverse: true}));原始功能：
var sort_by = function() { var fields = [].slice.call(arguments), n_fields = fields.length; return function(A,B) { var a, b, field, key, primer, reverse, result, i; for(i = 0; i < n_fields; i++) {result = 0;field = fields[i];key = typeof field === 'string' ? field : field.name;a = A[key];b = B[key];if (typeof field.primer !== 'undefined'){ a = field.primer(a); b = field.primer(b);}reverse = (field.reverse) ? -1 : 1;if (a<b) result = reverse * -1;if (a>b) result = reverse * 1;if(result !== 0) break; } return result; }};
