Can I define custom operator overloads in Javascript? [duplicate]

I agree that the equal function on the vector prototype is the best solution. Note that you can also build other infix-like operators via chaining.

function Vector(x, y, z) {    this.x = x;    this.y = y;    this.z = z;}Vector.prototype.add = function (v2) {    var v = new Vector(this.x + v2.x,                       this.y + v2.y,                       this.z + v2.z);    return v;}Vector.prototype.equal = function (v2) {    return this.x == v2.x && this.y == v2.y && this.z == v2.z;}

You can see online sample here.

Update: Here's a more extensive sample of creating a Factory function that supports chaining.

The best you can do if you want to stick with the == operator:

function Vector(x, y, z) {  this.x = x;  this.y = y;  this.z = z;}Vector.prototype.toString = function () {  return this.x + ";" + this.y + ";" + this.z;};var a = new Vector(1, 2, 3);var b = new Vector(1, 2, 3);var c = new Vector(4, 5, 6);alert( String(a) == b ); // truealert( String(a) == c ); // falsealert( a == b + "" );    // true again (no object wrapper but a bit more ugly)

No, JavaScript doesn’t support operator overloading. You will need to write a method that does this:

Vector.prototype.equalTo = function(other) {    if (!(other instanceof Vector)) return false;    return a.x == b.x && a.y == b.y && a.z == b.z;}

Then you can use that method like:

vect1.equalTo(vect2)