joint.all.js
function point(x, y) {
        if (!(this instanceof point))
            return new point(x, y);
        var xy;
        if (y === undefined && Object(x) !== x) {
            xy = x.split(_.indexOf(x, "@") === -1 ? " " : "@");
            this.x = parseInt(xy[0], 10);
            this.y = parseInt(xy[1], 10);
        } else if (Object(x) === x) {
            this.x = x.x;
            this.y = x.y;
        } else {
            this.x = x;
            this.y = y;
        }
    }
function point(x, y) {
        if (!(this instanceof point))
            return new point(x, y);
        var xy;
        if (y === undefined && Object(x) !== x) {
            xy = x.split(_.indexOf(x, "@") === -1 ? " " : "@");
            this.x = parseInt(xy[0], 10);
            this.y = parseInt(xy[1], 10);
        } else if (Object(x) === x) {
            this.x = x.x;
            this.y = x.y;
        } else {
            this.x = x;
            this.y = y;
        }
    }
* `point(10, 20)` * `new point(10, 20)` * `point('10 20')` * `point(point(10, 20))`