Unable to create a new instance in javascript

Question

the following is my code,

function hostile(x, y) {
        this.speed = 1;
        this.health = 100; 
        this.x = x; 
        this.y = y; 
        this.height = 32;
        this.width = 32;
        this.isDead = false;
        this.direction = 0;

        this.move = function(){
             context.clearRect(0,0,canvas1.width,canvas1.height); 
             if (this.x > canvas.width - 64) {

                 this.y += 10;
                 this.direction = 0;
             }
             if (this.x < 0) {
                 this.y += 10;
         }

             if (this.direction === 1) {
                 this.x += this.speed;
         } else {
               this.x -= this.speed;
         }
             if (this.x < 0) {
               this.direction = 1;
             }

             if (this.y > 420) {
             //this might have to be changed
                 this.x = 600;
             }
         }  
    };
//CREATING AN INSTANCE OF HOSTILE, THIS ISN'T WORKING FOR MULTIPLE INSTANCES, BUT WHY?

var hostile = new hostile(20,20);
var hostileA = new hostile(20,20);

I have hostile created and I have this instance being called in the update method, hostile.move() however the var hostile works, the var hostile does not, I have checked the code hostile is the only reference in the file.

BTW, jshint.com would have caught this for you.

SLaks
– SLaks

2013-10-23 14:09:29 +00:00
Commented Oct 23, 2013 at 14:09 — SLaks
– SLaks, Commented Oct 23, 2013 at 14:09

SLaks · Accepted Answer · 2013-10-23 13:22:17Z

2

var hostile = new hostile(20,20);

You just overwrote the hostile variable to refer to that instance rather than the constructor.

This is one of the reasons that constructors are UpperCamelCase by convention

answered Oct 23, 2013 at 13:22

SLaks

891k182 gold badges1.9k silver badges2k bronze badges

Sign up to request clarification or add additional context in comments.

Comments

mguimard · Accepted Answer · 2013-10-23 13:22:11Z

1

You're erasing your constructor with

var hostile = new hostile(20,20);

Then you can't create other hostile objects.

answered Oct 23, 2013 at 13:22

mguimard

1,89913 silver badges14 bronze badges

Collectives™ on Stack Overflow

Unable to create a new instance in javascript

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related