current community

your communities

more stack exchange communities

company blog
Stack Exchange Inbox Reputation and Badges
tour help
up vote 0 down vote favorite

So using the following part of my code, I've been trying to find the object's name ("object's name" refers to foo, bar, baz, and jar below. Sorry if that's the improper term, couldn't find any examples like this one on the web that termed them) using the values of the constructed function. To give an example:

function myFunction(){
  foo = new component(50, 50, "first", "red");
  bar = new component(50, 100, "sec", "red");
  baz = new component(0, 50, "third", "blue");
  jar = new component(0, 100, "fourth", "blue");
}
function component(x, y, id, color){
this.x = x;
this.y = y;
this.id = id;
this.color = color;
}

So if I have the value of both x and y, 50 and 100 respectively, what method would I use to make it so that the program will recognize that the constructor with these values is bar? If doing this using two values is impossible, using only one value is totally fine since I can always just combine the two into one. So far the best thing I've been able to come up with that somehwhat worked was that "foo instanceof component" is true, so maybe there's some method that I've yet to find that's basically the opposite of instance of? Thank you in advance.

share|improve this question
    
foo, bar, baz, and jar aren't constructors, they are objects. component is the only constructor here. I think I understand though. So you want to get x and y as input, and return the object that it's associated with? – 4castle 1 hour ago
    
Yes, exactly that. Thanks for the correct terms too. – Gnago 1 hour ago
up vote 3 down vote accepted

In your code foo, bar, baz and jar are variables, not constructors. These variables are pointing to objects that were created using the component function as the constructor.

It sounds like what you're trying to do is to find the object that was created using the specific values for x and y. One way to do that would be to have a lookup table where the keys are the combination of x and y, and the values are the objects:

var objects = {};
function component(x, y, id, color) {
    this.x = x;
    this.y = y;
    this.id = id;
    this.color = color;

    // Insert the current object into the lookup table
    objects[x + '_' + y] = this;
}

// Retreive an object from the lookup table
function findObject(x, y) {
    return objects[x + '_' + y];
}

One problem with this approach is that if you create two objects with the same x and y values, only the last one will be stored in the lookup table. You could solve that by storing an array of objects for each key instead.

share|improve this answer
1  
Good answer, I would however recommend making this self contained - check fiddle to see what I mean ... i.e., there's no way you can "accidentally" clobber objects, and using component.get makes it obvious you're getting a component – Jaromanda X 1 hour ago
    
Works until 2 objects have the same x and y values. :-( Also, if x and y change, the key to the object must change also. – RobG 42 mins ago

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.