function returns undefined in some pages

Question

I load a javascript file asynchronously and the file contains this line defined within a plugin defaults. It returns correct return value in some pages whereas in other pages the same file returns 'undefined' values. Any pointers?

login: '<p>Log in with your '+ fnc(code).name +' account</p>'

somewhere at the bottom of the same file I have defined the function:

 function fnc(s){
      if(s =='' || s == 'a'){
        this.name = 'name1';
        this.value = 'value1';
      }else if(s == 'b'){
        this.name = 'name2';
        this.value = 'value2';
      }else{
        this.name = 'name1';
        this.value = 'value1';
       }
      return this;
    }

For some reason, the function returns 'undefined'

UPDATE: "code" is a global variable that is present in some other file, depending on the value of that variable, I want to return different values from the function

UPDATE2: I want to return multiple values from the function, updated the code to reflect that.

How is this function being ran? `this` will be `window` unless you set its context. — gen_Eric, Dec 28 '12 at 15:35
What is `code`? Your function only sets `name` in three specific cases, so it (may) stay at `undefined` otherwise. — pimvdb, Dec 28 '12 at 15:36

score 2 · Answer 1 · answered Dec 28 '12 at 15:36

The value of this in that function is going to be either a reference to window or else undefined, depending on whether "strict mode" is in effect.

It really doesn't make a lot of sense for the function to be written like that. Seems like it should just be:

function fnc(s) {
  return s == '' || s == 'a' ? "name1" : s == "b" ? "name2" : null;
}

Then you'd just call it as fnc(code) with no need for a "name" property. As somebody else pointed out also, you don't make provisions for when the "code" is something other than the empty string, an "a", or a "b".

score 2 · Answer 2 · answered Dec 28 '12 at 15:36

2

Are you passing a value to fnc other than '', 'a' or 'b', as it will return undefined

answered Dec 28 '12 at 15:36

eleven11

362
2
3
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added 'else' condition to 'catch all' – neelmeg Dec 28 '12 at 15:57

score 2 · Accepted Answer · answered Dec 28 '12 at 15:37

2

this can refer to the document window, unless your writing an object, don't use this

function fnc(s){
    var rc = '';    
    if(s =='' || s == 'a'){
        rc = 'name1';
    } else if (s == 'b'){
        rc = 'name2';
    }
    return rc;
}

answered Dec 28 '12 at 15:37

keeg

3,990
8
49
97

right but now you won't get undefined, now you'll get an empty value instead or whatever `var rc` is set to. Still bad practice to have `this` floating in a function at the bottom of the page somewhere. – keeg Dec 28 '12 at 15:41
'this' was the problem, it got fixed now. – neelmeg Dec 28 '12 at 16:03

function returns undefined in some pages

3 Answers3