Function. Prototype. Bind knowledge point

 

1 var addnum = {// create a method and add num 2 num: 5, 3 fun: function (VAL) {4 return this. num + val; 5} 6} 7 8 function. prototype. bind = function (OBJ) {// function is an object, prototype. BIND is to add a new method 9 VaR method = This; 10 return function () {11 return method. apply (OBJ, arguments); 12} 13} 14 15 var foo1 = addnum. fun (3); 16 17 var addjson = {18 num: 1019}; 20 var foo2 = addnum. fun. BIND (addjson); 21 22 console. log (foo1); // The 823 console. log (foo2 (3); // 13

 

 

 

The bind and apply methods have been mentioned in the previous article. Please refer to the corresponding link.

Http://www.cnblogs.com/johnnylion/p/3937325.html

Http://www.cnblogs.com/johnnylion/p/3937456.html

 

Data Type

There are 6 data types in ecmascript. Includes five simple data types (also known as basic data types) and one complex data type.

 

Simple data type:

Undefined | null | Boolean | Number | string

 

Complex data types:

Object

 

Typeof Operator

Typeof can detect the Data Type of a given variable. Using the typeof operator for a value may return one of the following strings:

Undefined: if this value is undefined

Boolean: ***** Boolean

String: ***** string

Number: ***** Value

Object: * or null

Function: ***** Function

 

Example

var message = "some string";console.log(typeof message); // stringconsole.log(typeof (message)); // stringconsole.log(typeof 95); // number

 

Instanceof

O instanceof type: determines whether the object o belongs to the type. If O is an instance of the type subclass, it is also satisfied.

Example

1 var o=[];2 console.log(o instanceof Array); // true3 console.log(o instanceof Object); // true4 var f=function(){}5 console.log(f instanceof Function); // true6 console.log(f instanceof Object); // true

 

 

Reference similar to object | array | date | Regexp | Function

 

Function. Prototype. Bind knowledge point