How to call a child function inside a function from another function in Javascript?

Question

function Hello()
{
  function HelloAgain(){
  }
}

function MyFunction(){
...
}

Here I need to call the function HelloAgain() from MyFunction(). Can you suggest any possible solution for this scenario.

If `HelloAgain` is nested, it suggests that it shouldn't be used from outside the parent function. Why nest it in the first place if you need it outside of the function. And I don't think this would logically make sense. What if the child function used data from the parent function? If the parent function was never called, what data would the inner function use? — Carcigenicate, Jul 25 '17 at 15:25
That is sort of impossible.... unless you somehow expose it. — epascarello, Jul 25 '17 at 15:25
@VedPrakash are you sure about that duplicate? Both functions look top level, but in this question there is one nested function. — yuriy636, Jul 25 '17 at 15:27
How about return object from first function and inner function as method https://jsfiddle.net/Lg0wyt9u/2089/ — Nenad Vracar, Jul 25 '17 at 15:29
Funny thing. I just googled this AND THIS NON-ANSWER COMES UP — capitalaudience.com, Jan 01 '19 at 21:11

score 1 · Answer 1 · answered Jul 25 '17 at 15:38

1

You can't, the HelloAgain function is in a closure and is scoped to that closure.

You could return the HelloAgain function and then call it from anywhere you can call Hello.

function Hello () {
  function HelloAgain () {}
  return HelloAgain;
}

function MyFunction () {
  Hello().HelloAgain();
}

But that slightly weird.

More over you could use the this keyword to deal with the matter.

function Hello () {
  this.helloAgain = function helloAgain () {}
}

var hello = new Hello();

function MyFunction () {
  hello.helloAgain();
}

answered Jul 25 '17 at 15:38

Vishal Sakaria

Please explain that `this` will be `window` in that context (thus making `helloagain` a global variable), saying "you can use `this` to deal with the matter" is a little bit obscure. – yuriy636 Jul 25 '17 at 15:44
`this` is in the conext `Hello` not `window` https://jsfiddle.net/L09y3gcL/ – Vishal Sakaria Jul 25 '17 at 15:53
True, sorry, totally missed the `new Hello()` part. – yuriy636 Jul 25 '17 at 16:00

score 0 · Answer 2 · answered Jul 25 '17 at 15:25

0

You can't. The scope of HelloAgain il limited to the Hello function. This is the only way to make private scope in javascript.

answered Jul 25 '17 at 15:25

ema

2 Answers2