Method object in javascript

Question

I have written following code and it is not showing any alert.

var test = function(message) {
    this.show = function() {
        alert(message)
    }
}
(new test("hiii")).show();
(new test("helooo")).show();

When changed to following... Removed the bracket of - (new test("hiii")).show();

It shows both "hiii" and "helooo" alert.

Note: I did not make any changes to - (new test("helooo")).show();

var test = function(message) {
    this.show = function() {
        alert(message)
    }
}
new test("hiii").show(); // was(new test("hiii")).show();
(new test("helooo")).show();

Can anyone explain why?

@zerkms I copied that first block of code into the Firefox debug console and it got an error. — Pointy
– Pointy, Commented Jul 14, 2015 at 12:43
No, the semicolon wasn't in the original. @Tushar added the semicolon which I removed. — JJJ
– JJJ, Commented Jul 14, 2015 at 12:44
@BibinVenugopal it was not in the very initial revision of the question — zerkms
– zerkms, Commented Jul 14, 2015 at 12:45

Pointy · Accepted Answer · 2015-07-14 12:42:25Z

3

The problem, oddly enough, is with the fact that you left out the semicolon after your function expression:

var test = function(message){
    this.show = function() {
            alert(message)
    }
} // <-- missing semicolon

That means that the ( ... ) following the function expression is taken to be the argument list for a function call.

Add that missing semicolon and the first block of code will work.

answered Jul 14, 2015 at 12:42

Pointy

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Comments

abs · Accepted Answer · 2015-07-14 12:55:56Z

0

Since semicolon is missing it will take as self invoking function expression with argument new test("hiii") so use it like this

var test = function(message) {
   this.show = function() {
       alert(message)
 }
};
(new test("hiii")).show();
(new test("helooo")).show();

answered Jul 14, 2015 at 12:55

abs

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