如何在javascript中“唯一”重复n次函数？

Question

so I have some code that draws a path and a circle. the circle is animated across the path every single time the function is initiated. I simply want to create 10 paths, each with their own circle that animates across each path. When I simply execute the function 10 times, the paths are generated fine, however the circle all animate along the same, single path. what am I doing wrong here? Is the best method here to create a for(i=0) loop?

You can view my code on jfiddle , or take a look at it here:

function commerce() {
Raphael("commercebounce", function () {
            var r = this;   
            function pathfade() {
            var pa = .1,
                pb = .4, 
                pc = [0, 2], 
                pd = [50, 300], 
                pe = [150, 800], 
                pf = [150, 350], 
                pg = pd[0] + Math.random() * (pd[1] - pd[0]), 
                ph = pe[0] + Math.random() * (pe[1] - pe[0]), 
                pi = pf[0] + Math.random() * (pf[1] - pf[0]),
                bd = .1,
                be = .9,
                pathspot = bd + Math.random() * (be - bd),
                colours = ["215,10,45", "115,115,115"],
                stroke = ["", "- "];
                opacity = pa + Math.random() * (pb - pa), colour = "rgb(" + colours[Math.round(Math.random())] + ")", strokeW = pc[Math.round(Math.random())];
                pj = r.path("M 0 " + pg + " C 0 " + pg + " " + (ph - 100) + " " + pg + " " + ph + " 400 M " + ph + " 400 C " + ph + " 400 " + (ph + 100) + " " + pg + " 960 " + pi).attr({stroke: colour,"stroke-dasharray": stroke[Math.round(Math.random())],"opacity": 0});
                bh = r.circle(0, 0, 7, 7).attr({"stroke-width": this.strokeW,stroke: colour,"stroke-opacity": this.opacity,fill: "none","fill-opacity": 0}).onAnimation(function() {
                var t = this.attr("transform")})
                leng = pj.getTotalLength();
                r.customAttributes.along1 = function (v) {
                    var point = pj.getPointAtLength(v * leng);
                    return {
                        transform: "t" + [point.x, point.y] + "r" + point.alpha
                       }
                };
                return bh.attr({along1:0}), bh.animate({along1:pathspot},300), pj.animate({opacity:opacity},300), pj, bh
             }
pathfade();//how do i repeat this function n times?               
    }); 
}
commerce();

Answer 1

As far as I can see a simple loop should be fine. If you're interested this is the fastest way to loop in JavaScript:

var i = 10; while (i--) {
//Your code..
}

Answer 2

var n = 5; //or however much you want
for (var i = 0; i < n; i++){
    pathfade();
}

The for loop method is the simplest option here.

Answer 3

You need to break the pathfade() function into multiple simple functions that do only a few task.

There are two main problems. First, you're placing a semi-colon where there should be a comma during your variable declarations. Look at the stroke variable. Second, pathfade is returning multiple values when javascript only supports one. Remember that once you return from a function the rest of the statements don't get executed.

And lastly, use a for, do-while, or while loop to repeat your function calls.

Here's the fix. Sorry I didn't have time to refactor.

function commerce() {
    Raphael("commercebounce", function () {
        var r = this;
        function pathfade() {
            var pa = 0.5,
            pb = 0.9,
            pc = [0, 2],
            pd = [50, 300],
            pe = [150, 800],
            pf = [150, 350],
            pg = pd[0] + Math.random() * (pd[1] - pd[0]),
            ph = pe[0] + Math.random() * (pe[1] - pe[0]),
            pi = pf[0] + Math.random() * (pf[1] - pf[0]),
            bd = 0.1,
            be = 0.9,
            pathspot = bd + Math.random() * (be - bd),
            colours = ["215,10,45", "115,115,115"],
            stroke = ["", "- "],
            opacity = pa + Math.random() * (pb - pa),
            colour = "rgb(" + colours[Math.round(Math.random())] + ")",
            strokeW = pc[Math.round(Math.random())],
            pj = r.path("M 0 " + pg + " C 0 " + pg + " " + (ph - 100) + " " + pg + " " + ph + " 400 M " + ph + " 400 C " + ph + " 400 " + (ph + 100) + " " + pg + " 960 " + pi).attr({
                    stroke : colour,
                    "stroke-dasharray" : stroke[Math.round(Math.random())],
                    "opacity" : 0
                }),
            bh = r.circle(0, 0, 7, 7).attr({
                    "stroke-width" : this.strokeW,
                    stroke : colour,
                    "stroke-opacity" : this.opacity,
                    fill : "none",
                    "fill-opacity" : 0
                }).onAnimation(function () {
                    var t = this.attr("transform")
                }),
                leng = pj.getTotalLength();
            r.customAttributes.along1 = function (v) {
                var point = pj.getPointAtLength(v * leng);
                return {
                    transform : "t" + [point.x, point.y] + "r" + point.alpha
                }
            };
            bh.attr({
                along1 : 0
            });
            bh.animate({
                along1 : pathspot
            }, 300);
            pj.animate({
                opacity : opacity
            }, 300);
        }
        var i = 10;
        while( i-- ){
            pathfade();
        }
    });
}
commerce();

Demo: http://jsfiddle.net/VEdwG/6/

Your should read "The Elements of C# Style".

http://www.amazon.com/The-Elements-Style-Kenneth-Baldwin/dp/0521671590/ref=cm_cr-mr-title