嵌套JSON：属性长度未定义

Question

我正在尝试在D3JS中使用带有JSON的嵌套数组，却无法弄清为什么我在读取以下内容的行上遇到“属性长度未定义”错误：

.attr("d", function(d) { return line(d.points); }).

这是JSON：

[
{
    "aspectRatio": 1.247386759581881,
    "closed": 1,
    "xyData": [
        {
            "x0": 0.53078594712060867,
            "x1": 0.95454545454545459,
            "x2": 0.95454545454545459,
            "x3": 0.53078594712060867,
            "x4": 0.53078594712060867,
            "y0": 0.52936622215603868,
            "y1": 0.52936622215603868,
            "y2": 0.13179275296659432,
            "y3": 0.13179275296659432,
            "y4": 0.52936622215603868
        }
    ]
},
{
    "aspectRatio": 1.247386759581881,
    "closed": 1,
    "xyData": [
        {
            "x0": 0.045454545454545435,
            "x1": 0.41126403477001078,
            "x2": 0.41126403477001078,
            "x3": 0.045454545454545435,
            "x4": 0.045454545454545435,
            "y0": 0.86820724703340568,
            "y1": 0.86820724703340568,
            "y2": 0.44804437618547044,
            "y3": 0.44804437618547044,
            "y4": 0.86820724703340568
        }
    ]
}
]

这是代码：

function loadEss(filename,svgName,mainWidth){
var svgName;
d3.json(filename, function(error, data) {
    data.forEach(function(kv){
        kv.xyData.forEach(function(d) {
            d.points = [];
            aspect=1.5;
            for (var i = 0; d["x"+i] !== "" && (typeof d["x"+i] !== 'undefined'); i++) {
                d.points.push([mainWidth*d["x"+i], mainWidth/aspect*(d["y"+i])]);
            }
            console.log(d.points);
        });
    });

    var margin = {top: 0, right: 0, bottom: 0, left: 0},    
        width = mainWidth - margin.left - margin.right,             
        height = mainWidth/aspect - margin.top - margin.bottom; 

    svgName= d3.select("body")                                  
        .append("svg")                                      
            .attr("width", width + margin.left + margin.right)  
            .attr("height", height + margin.top + margin.bottom)
        .append("g")                                            
            .attr("transform", "translate(" + margin.left + "," + margin.top + ")"); 


    var line = 
    d3.svg.line() 
    .interpolate("linear-closed")
    ;

    svgName.selectAll("path")
        .data(data)
        .enter()
        .append("path")
        ;

    svgName.selectAll("path")
        .attr("d", function(d) { return line(d.points); })  
        .attr("stroke-linecap","round")
        .attr("stroke-linejoin","round")
        ;
});

};

这项工作基于之前的两个主题： 嵌套JSON数组和D3JS和d3JS：从CSV绘制线段

任何帮助将非常感激。

Answer 1

这是一个jsfiddle

您正在构建的点数组将存储在错误的位置，因此将d.points传递到line()时，在d.points以下d.points null。 代替d.points您需要kv.points ：

    kv.xyData.forEach(function(d) {
        kv.points = [];
        aspect=1.5;
        for (var i = 0; d["x"+i] !== "" && (typeof d["x"+i] !== 'undefined'); i++) {
            kv.points.push([mainWidth*d["x"+i], mainWidth/aspect*(d["y"+i])]);
        }
        console.log(kv.points);
    });