How to access function inside function without outer returning inner one
Question
I have got a function 'alpha', and there is another function 'beta' inside it. If I don't return beta in alpha, then how to access beta. Is there anyway of doing this? (Like, I can access alpha writing window.alpha(), as in global context alpha becomes a property of window object, then how to access beta as property, via window dom tree)?
<html> <head></head> <body> <script> function alpha() { console.log("hi"); function beta() { console.log("hello"); } } alpha(); //works window.alpha(); //works beta(); //it is directly not accessible. How to access it if alpha does not return it </script> </body> </html>
alpha() is in Window Dom but why not beta? (Even not inside alpha)
4 answers
solution1
3 ACCPTED 2018-04-12 07:37:51
Normally you can not do this thing either you can prefer these option but in these you have to call alpha once in order to get beta
//first option
(function alpha() {
console.log("hi");
function beta() {
console.log("hello");
}
window.beta = beta;
})()
//second option
Use this to create beta as property in alpha
function alpha() {
this.beta = function() {
console.log("hello");
}
}
let alphaObject = new alpha();
alphaObject.beta();
solution2
2 2018-04-12 07:32:07
If you don't want to return beta , you could return this and define beta as this.beta :
To access beta() , you simply need to call alpha().beta() .
function alpha() { console.log("hi"); this.beta = () => { console.log("hello"); } return this; } alpha().beta();
solution3
2 2018-04-12 07:49:11
The beta() method is private to function alpha. The way Javascript scoping works prevents you from directly accessing the inner functions . Create it as a property of alpha by using this.beta
solution4
1 2018-04-12 07:33:14
Declare beta as a member of alpha using this :
function alpha() { console.log("hi"); this.beta = function() { console.log("hello"); } } let a = new alpha(); a.beta();
You current implementation prevents JavaScript from accessing beta from outside of alpha . Read more about private functions in JavaScript.
Using this you can actually attach such methods to the instances of the function alpha . That's what I've done in this solution.
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