JS run function from constructor after object instantiation

Question

Is it possible to do this:

var hammer = new Hammer(); // create a new instance
hammer(nail); // really call Hammer.prototoype.hit(object);

I can figure it out on a raw object, but not when creating a new instance of an object. This is what I am running into:

function Hammer(options) {
  this.config = options.blah;
  this.hit(/* ? */);
  return this;
}

Hammer.prototype.hit = function(obj) {
  // ...
}

When I call the constructor, I want to pass in special options - not what nail to hit. However, when I call it later, I want to pass in a nail. I'm missing something.

Yes - but i'm looking to see if there's a shortcut so I don't have to expose hit. That's the point of this question. If there isn't, well that's why I asked if its possible. :) — dthree
– dthree, Commented Jun 11, 2015 at 18:20

Aadit M Shah · Accepted Answer · 2015-06-11 18:38:01Z

4

One solution is to not create a constructor function at all:

var hammer = newHammer();

hammer(nail);

hammer.clean();

function newHammer(options) {
    var config = options.blah;

    hit.clean = clean;

    return hit;

    function hit(obj) {
        // ...
    }

    function clean() {
        // ...
    }
}

To me, this is a much cleaner solution than messing around with constructors and prototypes.

edited Jun 11, 2015 at 18:38

answered Jun 11, 2015 at 18:27

Aadit M Shah

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6 Comments

dthree Over a year ago

True, but then could you create two different hammers with different properties? I might want my first hammer to be blue and the other one red!

Evan Davis Over a year ago

@dc2 of course; every object returned by the hammer factory is a new one.

dthree Over a year ago

Well, that makes you a boss, then.

dthree Over a year ago

Eh - in trying this, one side effect is that you can't then access any other functions. How could I do hammer(nail) as well as hammer.clean()? Again jQuery seems to accomplish this.

Aadit M Shah Over a year ago

@dc2 I updated my answer showing how to call hammer.clean. This is the way jQuery does it as well.

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