Using JavaScript functions as "classes": What am I doing wrong here? -


here's javascript "class" far: 

    function snake(c, c_h, c_w)     {              this.linksize = 10; // size of snake unit, in pixels              /* on instantiation, snake direction down , has 1 link */             this.dy = this.linksize;             this.dx = 0;             this.link = c.rect(c_h/2, c_w/2, this.linksize, this.linksize);             this.link.attr("fill", "#d7a900");             this.body = [link];              /* event listener changing direction of                snake arrow keys on keyboard             */             this.redirect = function(dirnum)             {                 switch (dirnum)                 {                     /*                         dirnum corresponds                         1 ---> right                         2 ---> down                         3 ---> left                         4 --->                     */                     case 1:                          this.dx = this.linksize;                         this.dy = 0;                         break;                      case 2:                         this.dx = 0;                         this.dy = this.linksize;                         break;                      case 3:                         this.dx = -this.linksize;                         this.dy = 0;                         break;                      case 4:                         this.dx = -this.linksize;                         this.dy = 0;                         break;                      default: // never happens                         break;                 }              }             this.move = function()             {                 /*                     /////                  */                  var temp = body[0];                 body[0].translate(this.dx, this.dy);                 (var = 1, j = body.length; < j; ++i)                 {                     body[i] = temp;                     temp = body[i];                 }             }              setinterval(this.move());     }

i have 2 problems being reported in google chrome console:

  • uncaught referenceerror: link not defined (on this.link.attr("fill", "#d7a900"); line).
  • uncaught typeerror: undefined not function (whenever press arrow key)

does have insight why these problems occurring? using this. keyword correctly?

uncaught referenceerror: link not defined mean call c.rect() returns undefined or null.

"uncaught typeerror: undefined not function (whenever press arrow key)"

there no event handling visible in code, might follow-up error.

triple check (using console.log) c correctly passed function , return value of c.rect() is.


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