44         check: function (arg) { return typeof (arg) === 'boolean'; }  method
47         check: function (arg) { return typeof (arg) === 'function'; }  method
50         check: function (arg) { return typeof (arg) === 'string'; }  method
53         check: function (arg) {  method
58         check: function (arg) {  method
63         check: function (arg) {  method
68         check: function (arg) { return Buffer.isBuffer(arg); },  method
72         check: function (arg) { return Array.isArray(arg); },  method
76         check: function (arg) { return arg instanceof Stream; },  method
81         check: function (arg) { return arg instanceof Date; },  method
86         check: function (arg) { return arg instanceof RegExp; },  method
91         check: function (arg) {  method