What does call (this) mean in x.f2.call (this)

function X(){
    return object = {
        name:"object",
        f1(x){
            x.f2.call(this)        
        },
        f2(){
            console.log(this)
        }
    }
}

var options = {
    name:"options",
    f1(){},
    f2(){
        console.log(this)    
    }
}

var x = X()
x.f1(options)
Javascript
Mar.16,2021
The function of

call is to change the this value of a function call and provide parameters for the function call.

var x = X () , when x is the object object,
x.f1 (options) , because F1 is called as an attribute of the global variable x , when executing x.f1 , the this in the method points to the global variable x , passing in the parameter options . 

f1(x){
    x.f2.call(this) // thisxxxxoptions
}

replace the variables in the above code: 

options.f2.call(x) // xoptionsthisx
When

options.f2 is executed, because f2 is called as an attribute of options , by default this points to the options object, but call (x) is used, that is, when the method is called, explicitly set this to point to the global variable x : 

f2(){
    console.log(this) // thisxx
}

Previous: Spring boot customizes 404 error page @ ControllerAdvice mode

Next: About WeChat Mini Programs's request interface.

css mysql arrays josn react html typescript webpack npm sass R objective-c .net sql-server jquery python-3.x angularjs django angular excel regex iphone ajax linux xml pandas vba spring database wordpress string wpf xcode windows bash postgresql oracle multithreading eclipse list firebase algorithm macos forms image scala visual-studio azure bootstrap spring-boot react-native python-2.7 docker performance function winforms matlab powershell apache dataframe api sqlite numpy rest shell selenium flutter dart maven loops qt swing android-studio csv express file class tensorflow sorting codeigniter perl
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b3307a-2be52.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b3307a-2be52.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
Need Help?