javascript 数据类型的判断

function isBoolean(value) { return typeof value === 'boolean'; } function isNumber(value) { return typeof value === 'number'; } function isString(value) { return typeof value === 'string'; } function isFunction(value) { return typeof value === 'function'; } var isArray = Array.isArray; function isDate(value) { return toString.call(value) === '[object Date]'; } function isRegExp(value) { return toString.call(value) === '[object RegExp]'; } function isObject(value) { return value !== null && typeof value === 'object'; } function isUndefined(value) { return typeof value === 'undefined'; } function isDefined(value) { return typeof value !== 'undefined'; } function isBlankObject(value) { return value !== null && typeof value === 'object' && !getPrototypeOf(value); } function isFile(obj) {return toString.call(obj) === '[object File]';} function isFormData(obj) {return toString.call(obj) === '[object FormData]';} function isBlob(obj) {return toString.call(obj) === '[object Blob]';} function isWindow(obj) {return obj && obj.window === obj;}

var class2type = {}; "Boolean Number String Function Array Date RegExp Object Error Symbol" .split( " " ) .forEach(function(element,index){ class2type[ "[object " + element + "]" ] = element.toLowerCase(); }); function type(obj) { if ( obj == null ) { return obj + ""; } return typeof obj === "object" || typeof obj === "function" ? class2type[ toString.call( obj ) ] || "object" : typeof obj; }