JavaScript Function 类似变量

Question

I want to use this function to call between results:

Working Result:

function flag1(newflag){
    console.log('This is'+newflag+' Got it?')
}

flag1('My_Flag')

// Result: This is My Flag Got it?

Not showing anything / Not Working:

function flag2(newflag){
    'This is '+newflag+' Got it?'
}

flag2('My_Flag')

// Result: <Nothing>

I know 2nd Example is Dumb but what else can i think of? My Goal is to send this in response with other stuff like above: This is My Flag Got it?

For example:

res.send('Blah Blah Blah '+flag2('My_Flag')+' Blah Blah Blah')

Expected Result:

Blah Blah Blah My_Flag Blah Blah Blah

This Question is based on Expressjs, but others might be able to help too

PS: This is for CTF or capture the flag nothing about countries these will be diffrent and unique everywhere thats why im using functions...

Answer 1

In your second example 'This is '+newflag+' Got it?' creates a string.

That is all it does.

It doesn't pass it to another function (like console.log or res.send ).

It doesn't assign it to a variable.

It doesn't assign it to a property of an object.

It doesn't return it so it can be used on the left hand side of flag2('My_Flag') (not that you have anything on the left hand side of that function call … although you do in the later example: res.send('Blah Blah Blah '+flag2('My_Flag')+' Blah Blah Blah') ).

Since you don't do anything, the string is thrown away immediately after it is created (unless the compiler optimises the string creation away entirely).

---

If you want to do something with the string, then you have to write code which does that.

Answer 2

This Worked:

function flag2(newflag){
   return (newflag);      
}

res.send('Blah Blah Blah '+flag2('My_Flag')+' Blah Blah Blah')

Its so simple, forgot return