Calling Superclass Method From Subclass - JavaScript
canvas, inheritance, javascript, subclass, superclass
Solution
Adapting this answer to your code:
function Entity(x, y) {
this.x = x;
this.y = y;
this.tick = function() {
//Do generic stuff
}
}
function Player(x, y) {
this.parent.constructor.call(this, x, y);
var oldtick = this.tick;
this.tick = function() {
//Do player-specific stuff
oldtick.call(this);
}
}
Player.prototype = Object.create(Entity.prototype);
Player.prototype.constructor = Player;
Player.prototype.parent = Entity.prototype;
Problem
Possible Duplicate: set attribute with javascript super method I am trying to create a simple game in HTML5 for fun. I have an Entity class that is supposed to be the superclass of the Player class. ``` function Entity(x, y) { this.x = x; this.y = y; this.tick = function() { //Do generic stuff } } function Player(x, y) { this.parent.constructor.call(this, x, y); this.tick = function() { //Do player-specific stuff this.parent.tick.call(this); } } Player.prototype = new Entity(); Player.prototype.constructor = Player; Player.prototype.parent = Entity.prototype; ``` The problem is at this line: ``` this.parent.tick.call(this); ``` I get an error displayed in the JavaScript console of chrome: "Uncaught TypeError: Cannot call method 'call' of undefined". I don't get it and I've spent a long time trying to find posts of a similar issue. My call to the superclass' constructor works fine but the call to the superclass' tick method does not work. I'm very new to making games so I have no idea if this a good setup (calling superclass tick from subclass tick). If there is a better, more typical way that people use, please tell. Thanks.