calling a method from another function in JS (TypeError exception)

Question

I guess it's really a newbie error, but I can't get it running. I have an "calculator" object t, which contains a lot of function to calculate values. I need to use these functions from my "calculator" object to get some values in another function. I striped it down to the following, but I get an TypeError exceptio when I call the t.hello() method. Any ideas?

 var t = new T();
 two();

 function T() {
     function hello() {
         alert("hello");
     }
 }

 function two() {

     t.hello();

 }

http://jsfiddle.net/4Cc4F/

Actually hello in your example is not a method, it is a local function defined inside other function — hindmost
– hindmost, Commented Aug 5, 2014 at 9:31

Cerbrus · Accepted Answer · 2014-08-05 09:30:15Z

3

You'll need to return an object that contains the function:

function T() {
    return {
        'hello': function () {
            alert("hello");
        }
    }
}

Or specifically define it as an function in T's scope:

function T() {
    this.hello = function() {
        alert("hello");
    }
}

Fiddle

answered Aug 5, 2014 at 9:30

Cerbrus

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7 Comments

audio_developer Over a year ago

I see, thanks! But one additional. How do I call "hello" inside from T now?

Cerbrus Over a year ago

@audio_developer: In the second example, you can use this.hello(), within T. You can't when using the first example.

audio_developer Over a year ago

thanks again. I tried exactly that before I asked, but did a typo for the call "this.hello(}" ... I guess this means I need a short break. :-) have a good day!

audio_developer Over a year ago

I discovered another question: Is this a good style to call hello from an inner function with that? jsfiddle.net/9H4JM

Cerbrus Over a year ago

@audio_developer: Yea, that works too. That way, you can create private functions.

|

Mritunjay · Accepted Answer · 2014-08-05 09:31:09Z

1

function hello is in local scope of T.

define T like this.

function T() {
     this.hello = function() {
         alert("hello");
     }
 }

answered Aug 5, 2014 at 9:31

Mritunjay

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Comments

Mayur Borad · Accepted Answer · 2014-08-05 09:49:26Z

0

Try this,

var t = new T();
two();
function T() {
     this.hello = function () {
         alert("hello");
     }
 }    
 function two() {    
     t.hello();    
 }

see this : http://jsfiddle.net/4Cc4F/2/

answered Aug 5, 2014 at 9:49

Mayur Borad

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