延迟打破我的动画

Question

你好，有人可以解释一下为什么我的动画会中断吗？所以我有这个圈子基本上遵循一条路径，因为彼此之上我需要一种方法来为每一个添加延迟，以便它们在屏幕上正确显示。

  var test = svgContainer.selectAll('.test')
        .data(testData)
        .attr("r", 10)
        .attr("transform", "translate(" + testData[0].x + "," +
                   testData[0].y + ")");


  var transitionFrom = test;

        for (var i = 1; i < testData.length; i++) {

            transitionFrom = transitionFrom.transition()
                    .duration(testData[i].speed)
                    .ease("linear")
                    .attr("transform", "translate(" + testData[i].x + "," +
                            testData[i].y + ")");


        }

每当我尝试添加像这样的.delay（）时

        var transitionFrom = test;

        for (var i = 1; i < testData.length; i++) {

            transitionFrom = transitionFrom.transition()
                    .duration(testData[i].speed)
                    **.delay(something here)**
                    .ease("linear")
                    .attr("transform", "translate(" + testData[i].x + "," +
                            testData[i].y + ")");


        }

我的动画片断了。