JS IsArray, typeof, Instanceof

Array.isarray ()

Used to verify that arrays are not

        var a = [Console.log]        (typeof a);   // Object        Console.log (Array.isarray (a));   // true

It can be seen that typeof does not validate the array, although Array.isarray () can verify the array, but IE8 is incompatible

        var a = [Object.prototype.toString.call]        alert ((a))  //  [Object Array]

This method can be compatible with IE8 and the following browsers

typeof

        function foo () {}        Console.log (typeof foo);  // function        Console.log (typeofnull//  object        console.log (typeof undefined);  // undefined        Console.log (typeof ' a ');    //   string        console.log (typeof 1);    //  Number

Here null is the basic type, not an object, this is a JS bug. There is also a notable place to watch:

null);  // true

Because undefined is derived from null in JS

instanceof

        function foo () {}         var New foo ()         instanceof foo);   // true

Instanceof is a prototype chain to find, if the display prototype object of function Foo is on the implicit prototype chain of a object, it returns true, otherwise false

The green one is the prototype chain of object A.

JS IsArray, typeof, Instanceof