JS Array type detection

In strongly typed languages, array type detection is a very easy thing (typeof can be solved), and in the weak language JS data type is easily confused.

The common data types in JS are: Number, String, Boolean, Undefined, function, array, object, and null. The following first Test with typeof:

var k = 9; Console.log (typeof K);  //  Number

The detection number can be detected with TypeOf.

var k = "string"; Console.log (typeof K);  // string

The detection string can be detected with TypeOf.

var true ; Console.log (typeof K);   // Boolean

The detection Boolean can be detected with TypeOf.

var U;console.log (typeof u);  // undefined

Detection undefined can also be detected with TypeOf.

var function () {};console.log (typeof F);   // function

Function can also be detected with TypeOf.

var NULL ; Console.log (typeof T);   // Object var array = [];console.log (typeof//objectvar obj =  {};console.log (typeof obj);    // Object

Using typeof to detect Null,array and object detection is an object. It appears that these three data structures need to be handled in a special way.

function type (o) {     returnnull)? "Null": (typeof  o)  }

Special handling of NULL is performed first, in order to see if array and object have other properties to judge.

var array = []; var toString =//[object Array]var obj = {}; Console.log ( Tostring.apply (obj)); // [Object Object]

OK, by detecting other data types: regexp and date can also be detected in this way:

var regex =/^\s+/var toString = Object.prototype.tostring;console.log (tostring.apply (regex));   // [Object RegExp] var New date (); Console.log (Tostring.apply (Date));   // [Object Date]

Finally, let's write a generic function to detect the JS data type:

functionTypeOf (e) {var_tostring =Object.prototype.toString; var_type = {        "Undefined": "Undefined",        "Number": "Number",        "Boolean": "Boolean",        "String": "String",        "Function": "Function",        "[Object RegExp]": "Regex",        "[Object array]": "Array",        "[Object Date]": "Date"    }    return_type[typeofE] | | _type[_tostring.call (e)] | | E? ' object ': ' null ');}

I see some other ways to detect data types in Zepto.js, and you can refer to:

varToString = ({}). tostring;//quite ingenious.  functionIsfunction (value) {returnTostring.call (value) = = "[Object Function]" }functionIsObject (value) {returnValueinstanceofObject}//Returns false for True,new object simultaneous arguments for objects that are defined by literal values and new//The prototype chain of the constructor of the new object simultaneous parameter has no isprototypeof property, while the constructor's __proto__ object has a prototype chain. functionIsplainobject (value) {varKey, ctor//returns if it is not an object type.     if(Tostring.call (value)!== "[Object Object]")return false     //gets the properties or objects in the prototype chain of the objectctor = (isfunction (value.constructor) &&Value.constructor.prototype)//There is no object or attribute in the prototype chain, or there is no property isprototypeof, and returns false    if(!ctor | |!hasownproperty.call (ctor, ' isprototypeof '))return false     for(Keyinchvalue); returnKey = = = Undefined | |Hasownproperty.call (value, key)}functionIsArray (value) {returnValueinstanceofArray}functionLikearray (obj) {//class array, not a real array, is an object that has a member type of "Length"    return typeofObj.length = = ' Number ' }

JS Array type detection