javascript: defining var in constructor makes it unusable

Question

I have written this code in javascript:

var engiszik;
var numOfCitizens = 10;

function Engiszi()
{
  var chance = random(0, 100);
  this.type = chance < 67 ? "r" : (chance < 87 ? "o" : "p");
  this.mood = ((type === "o") ? random(60, 100, false) : (type === "p" ? random(0, 20) : random(0, 100, false)));
  this.changePlace = random(0, 15, false);
}

initialize();
function initialize()
{
  engiszik = [];
  for(var i = 0; i < numOfCitizens; i ++)
    engiszik.push(new Engiszi());
}

random works correctly and returns a number. The ?: parts also seem to be correct (not entirely sure: can the lack of parentheses cause errors in it?).

When I load the page, I get the error "type not found" at the line engiszik.push(new Engiszi());. If I remove the variable chance from the constructor of Engiszi (and the things that use it), it seems to work.

What causes this? Does the var in the constructor change Engiszi into a normal function instead of a constructor? How can I find a way around this (I really need chance, but I don't want to declare it as a global variable if possible)?

var in a ctor is allowed. Something else is going funny with your code. Since you've only posted part of it (your example doesn't run), I imagine it's in one of the other parts. — ssube
– ssube, Commented Aug 17, 2015 at 16:35
Have you looked at returning it from the Engiszi function? — Frank Adrian
– Frank Adrian, Commented Aug 17, 2015 at 16:35

Paul S. · Accepted Answer · 2015-08-17 16:35:46Z

3

Lets follow where the error is coming from back beyond the invocation line

"type not found" at the line engiszik.push(new Engiszi());

Step into new Engiszi(), look for type,

this.mood = ((type === "o") ? random(60, 100, false) : (type === "p" ? random(0, 20) : random(0, 100, false)));
//            ^^^^                                      ^^^^

Where is type defined? did you mean this.type?

answered Aug 17, 2015 at 16:35

Paul S.

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1 Comment

sisisisi Over a year ago

Yes. I thought it meant the type "Engiszi", but apparently it was this.type. Adding "this." to "type" solved the problem.

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