Cubic Bezier interpolation class for javascript animation.

cubicBezier.class.js

function cubicBezier(x1, y1, x2, y2){
    var p1 = [x1, y1], p2 = [x2, y2];
    this.calculate = function(t){
        return [
            0 * Math.pow(1-t, 3) + p1[0] * 3 * Math.pow(1-t, 2) * t + p2[0] * 3 * (1-t) * Math.pow(t, 2) + 1 * Math.pow(t, 3),
            0 * Math.pow(1-t, 3) + p1[1] * 3 * Math.pow(1-t, 2) * t + p2[1] * 3 * (1-t) * Math.pow(t, 2) + 1 * Math.pow(t, 3),
        ];
    };
}

// Example
// var easeOut = new cubicBezier(0,0,0.6,1);
// easeOut.calculate(0.5); //[0.35, 0.5]