Javascript d3.json：“未捕获的类型错误：无法读取未定义的属性 'children'”
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/13715891/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
d3.json: "Uncaught TypeError: Cannot read property 'children' of undefined"
提问by user391339
I am trying out d3 as a tool for representing biological data.
我正在尝试将 d3 作为表示生物数据的工具。
I am trying to open the following example in my chrome browser so that I can understand how it works. Unfortunately I get the following error "Uncaught TypeError: Cannot read property 'children' of undefined ".
我试图在我的 chrome 浏览器中打开以下示例，以便我了解它是如何工作的。不幸的是，我收到以下错误“未捕获的类型错误：无法读取未定义的属性 'children'”。
If you click the link, the source code for both the .html file and the .json file are displayed below the output of the visualization. Clearly the visualization is working on the above page. I'm not sure what I could be doing wrong.
如果单击该链接，则 .html 文件和 .json 文件的源代码将显示在可视化输出的下方。显然，可视化在上面的页面上工作。我不确定我可能做错了什么。
I have copied both the index.html file and the flare.json file to a directory on a web server. If I tried to load it from a local file I got another error: XMLHttpRequest cannot load file:///C:/Users/(..omitted..)/flare.json. Cross origin requests are only supported for HTTP.
我已将 index.html 文件和flare.json 文件复制到 Web 服务器上的目录中。如果我尝试从本地文件加载它，我会收到另一个错误：XMLHttpRequest 无法加载 file:///C:/Users/(..omitted..)/flare.json。跨源请求仅支持 HTTP。
The flare.json file indeed can be loaded from the webserver (I can see its text content). It contains the tree data I am trying to graph.
flare.json 文件确实可以从网络服务器加载（我可以看到它的文本内容）。它包含我试图绘制的树数据。
Clearly the flare.json file begins as follows:
很明显，flare.json 文件的开头如下：
{"name": "flare","children": [...
{"name": "flare","children": [...
Unfortunately d3.json is having trouble parsing this information...
不幸的是，d3.json 在解析这些信息时遇到了麻烦……
If it helps, here is the .html file I am trying to open in Chrome:
如果有帮助，这是我尝试在 Chrome 中打开的 .html 文件：
<!DOCTYPE html>
<html>
<head>
<title>heirarchical graph</title>
<meta charset="utf-8">
<style>
.node circle {
fill: #fff;
stroke: steelblue;
stroke-width: 1.5px;
}
.node {
font: 10px sans-serif;
}
.link {
fill: none;
stroke: #ccc;
stroke-width: 1.5px;
}
</style>
<script type="text/javascript"
src="https://raw.github.com/mbostock/d3/master/d3.v2.min.js">
</script>
</head>
<body>
<script>
var diameter = 960;
var tree = d3.layout.tree()
.size([360, diameter / 2 - 120])
.separation(function(a, b) { return (a.parent == b.parent ? 1 : 2) / a.depth; });
var diagonal = d3.svg.diagonal.radial()
.projection(function(d) { return [d.y, d.x / 180 * Math.PI]; });
var svg = d3.select("body").append("svg")
.attr("width", diameter)
.attr("height", diameter - 150)
.append("g")
.attr("transform", "translate(" + diameter / 2 + "," + diameter / 2 + ")");
d3.json("flare.json", function(error, root) {
var nodes = tree.nodes(root),
links = tree.links(nodes);
var link = svg.selectAll(".link")
.data(links)
.enter().append("path")
.attr("class", "link")
.attr("d", diagonal);
var node = svg.selectAll(".node")
.data(nodes)
.enter().append("g")
.attr("class", "node")
.attr("transform", function(d) { return "rotate(" + (d.x - 90) + ")translate(" + d.y + ")"; })
node.append("circle")
.attr("r", 4.5);
node.append("text")
.attr("dy", ".31em")
.attr("text-anchor", function(d) { return d.x < 180 ? "start" : "end"; })
.attr("transform", function(d) { return d.x < 180 ? "translate(8)" : "rotate(180)translate(-8)"; })
.text(function(d) { return d.name; });
});
d3.select(self.frameElement).style("height", diameter - 150 + "px");
</script>
</body>
</html>
And, here is the flare.json file:
而且，这是flare.json 文件：
{
"name": "flare",
"children": [
{
"name": "analytics",
"children": [
{
"name": "cluster",
"children": [
{"name": "AgglomerativeCluster", "size": 3938},
{"name": "CommunityStructure", "size": 3812},
{"name": "HierarchicalCluster", "size": 6714},
{"name": "MergeEdge", "size": 743}
]
},
{
"name": "graph",
"children": [
{"name": "BetweennessCentrality", "size": 3534},
{"name": "LinkDistance", "size": 5731},
{"name": "MaxFlowMinCut", "size": 7840},
{"name": "ShortestPaths", "size": 5914},
{"name": "SpanningTree", "size": 3416}
]
},
{
"name": "optimization",
"children": [
{"name": "AspectRatioBanker", "size": 7074}
]
}
]
},
{
"name": "animate",
"children": [
{"name": "Easing", "size": 17010},
{"name": "FunctionSequence", "size": 5842},
{
"name": "interpolate",
"children": [
{"name": "ArrayInterpolator", "size": 1983},
{"name": "ColorInterpolator", "size": 2047},
{"name": "DateInterpolator", "size": 1375},
{"name": "Interpolator", "size": 8746},
{"name": "MatrixInterpolator", "size": 2202},
{"name": "NumberInterpolator", "size": 1382},
{"name": "ObjectInterpolator", "size": 1629},
{"name": "PointInterpolator", "size": 1675},
{"name": "RectangleInterpolator", "size": 2042}
]
},
{"name": "ISchedulable", "size": 1041},
{"name": "Parallel", "size": 5176},
{"name": "Pause", "size": 449},
{"name": "Scheduler", "size": 5593},
{"name": "Sequence", "size": 5534},
{"name": "Transition", "size": 9201},
{"name": "Transitioner", "size": 19975},
{"name": "TransitionEvent", "size": 1116},
{"name": "Tween", "size": 6006}
]
},
{
"name": "data",
"children": [
{
"name": "converters",
"children": [
{"name": "Converters", "size": 721},
{"name": "DelimitedTextConverter", "size": 4294},
{"name": "GraphMLConverter", "size": 9800},
{"name": "IDataConverter", "size": 1314},
{"name": "JSONConverter", "size": 2220}
]
},
{"name": "DataField", "size": 1759},
{"name": "DataSchema", "size": 2165},
{"name": "DataSet", "size": 586},
{"name": "DataSource", "size": 3331},
{"name": "DataTable", "size": 772},
{"name": "DataUtil", "size": 3322}
]
},
{
"name": "display",
"children": [
{"name": "DirtySprite", "size": 8833},
{"name": "LineSprite", "size": 1732},
{"name": "RectSprite", "size": 3623},
{"name": "TextSprite", "size": 10066}
]
},
{
"name": "flex",
"children": [
{"name": "FlareVis", "size": 4116}
]
},
{
"name": "physics",
"children": [
{"name": "DragForce", "size": 1082},
{"name": "GravityForce", "size": 1336},
{"name": "IForce", "size": 319},
{"name": "NBodyForce", "size": 10498},
{"name": "Particle", "size": 2822},
{"name": "Simulation", "size": 9983},
{"name": "Spring", "size": 2213},
{"name": "SpringForce", "size": 1681}
]
},
{
"name": "query",
"children": [
{"name": "AggregateExpression", "size": 1616},
{"name": "And", "size": 1027},
{"name": "Arithmetic", "size": 3891},
{"name": "Average", "size": 891},
{"name": "BinaryExpression", "size": 2893},
{"name": "Comparison", "size": 5103},
{"name": "CompositeExpression", "size": 3677},
{"name": "Count", "size": 781},
{"name": "DateUtil", "size": 4141},
{"name": "Distinct", "size": 933},
{"name": "Expression", "size": 5130},
{"name": "ExpressionIterator", "size": 3617},
{"name": "Fn", "size": 3240},
{"name": "If", "size": 2732},
{"name": "IsA", "size": 2039},
{"name": "Literal", "size": 1214},
{"name": "Match", "size": 3748},
{"name": "Maximum", "size": 843},
{
"name": "methods",
"children": [
{"name": "add", "size": 593},
{"name": "and", "size": 330},
{"name": "average", "size": 287},
{"name": "count", "size": 277},
{"name": "distinct", "size": 292},
{"name": "div", "size": 595},
{"name": "eq", "size": 594},
{"name": "fn", "size": 460},
{"name": "gt", "size": 603},
{"name": "gte", "size": 625},
{"name": "iff", "size": 748},
{"name": "isa", "size": 461},
{"name": "lt", "size": 597},
{"name": "lte", "size": 619},
{"name": "max", "size": 283},
{"name": "min", "size": 283},
{"name": "mod", "size": 591},
{"name": "mul", "size": 603},
{"name": "neq", "size": 599},
{"name": "not", "size": 386},
{"name": "or", "size": 323},
{"name": "orderby", "size": 307},
{"name": "range", "size": 772},
{"name": "select", "size": 296},
{"name": "stddev", "size": 363},
{"name": "sub", "size": 600},
{"name": "sum", "size": 280},
{"name": "update", "size": 307},
{"name": "variance", "size": 335},
{"name": "where", "size": 299},
{"name": "xor", "size": 354},
{"name": "_", "size": 264}
]
},
{"name": "Minimum", "size": 843},
{"name": "Not", "size": 1554},
{"name": "Or", "size": 970},
{"name": "Query", "size": 13896},
{"name": "Range", "size": 1594},
{"name": "StringUtil", "size": 4130},
{"name": "Sum", "size": 791},
{"name": "Variable", "size": 1124},
{"name": "Variance", "size": 1876},
{"name": "Xor", "size": 1101}
]
},
{
"name": "scale",
"children": [
{"name": "IScaleMap", "size": 2105},
{"name": "LinearScale", "size": 1316},
{"name": "LogScale", "size": 3151},
{"name": "OrdinalScale", "size": 3770},
{"name": "QuantileScale", "size": 2435},
{"name": "QuantitativeScale", "size": 4839},
{"name": "RootScale", "size": 1756},
{"name": "Scale", "size": 4268},
{"name": "ScaleType", "size": 1821},
{"name": "TimeScale", "size": 5833}
]
},
{
"name": "util",
"children": [
{"name": "Arrays", "size": 8258},
{"name": "Colors", "size": 10001},
{"name": "Dates", "size": 8217},
{"name": "Displays", "size": 12555},
{"name": "Filter", "size": 2324},
{"name": "Geometry", "size": 10993},
{
"name": "heap",
"children": [
{"name": "FibonacciHeap", "size": 9354},
{"name": "HeapNode", "size": 1233}
]
},
{"name": "IEvaluable", "size": 335},
{"name": "IPredicate", "size": 383},
{"name": "IValueProxy", "size": 874},
{
"name": "math",
"children": [
{"name": "DenseMatrix", "size": 3165},
{"name": "IMatrix", "size": 2815},
{"name": "SparseMatrix", "size": 3366}
]
},
{"name": "Maths", "size": 17705},
{"name": "Orientation", "size": 1486},
{
"name": "palette",
"children": [
{"name": "ColorPalette", "size": 6367},
{"name": "Palette", "size": 1229},
{"name": "ShapePalette", "size": 2059},
{"name": "SizePalette", "size": 2291}
]
},
{"name": "Property", "size": 5559},
{"name": "Shapes", "size": 19118},
{"name": "Sort", "size": 6887},
{"name": "Stats", "size": 6557},
{"name": "Strings", "size": 22026}
]
},
{
"name": "vis",
"children": [
{
"name": "axis",
"children": [
{"name": "Axes", "size": 1302},
{"name": "Axis", "size": 24593},
{"name": "AxisGridLine", "size": 652},
{"name": "AxisLabel", "size": 636},
{"name": "CartesianAxes", "size": 6703}
]
},
{
"name": "controls",
"children": [
{"name": "AnchorControl", "size": 2138},
{"name": "ClickControl", "size": 3824},
{"name": "Control", "size": 1353},
{"name": "ControlList", "size": 4665},
{"name": "DragControl", "size": 2649},
{"name": "ExpandControl", "size": 2832},
{"name": "HoverControl", "size": 4896},
{"name": "IControl", "size": 763},
{"name": "PanZoomControl", "size": 5222},
{"name": "SelectionControl", "size": 7862},
{"name": "TooltipControl", "size": 8435}
]
},
{
"name": "data",
"children": [
{"name": "Data", "size": 20544},
{"name": "DataList", "size": 19788},
{"name": "DataSprite", "size": 10349},
{"name": "EdgeSprite", "size": 3301},
{"name": "NodeSprite", "size": 19382},
{
"name": "render",
"children": [
{"name": "ArrowType", "size": 698},
{"name": "EdgeRenderer", "size": 5569},
{"name": "IRenderer", "size": 353},
{"name": "ShapeRenderer", "size": 2247}
]
},
{"name": "ScaleBinding", "size": 11275},
{"name": "Tree", "size": 7147},
{"name": "TreeBuilder", "size": 9930}
]
},
{
"name": "events",
"children": [
{"name": "DataEvent", "size": 2313},
{"name": "SelectionEvent", "size": 1880},
{"name": "TooltipEvent", "size": 1701},
{"name": "VisualizationEvent", "size": 1117}
]
},
{
"name": "legend",
"children": [
{"name": "Legend", "size": 20859},
{"name": "LegendItem", "size": 4614},
{"name": "LegendRange", "size": 10530}
]
},
{
"name": "operator",
"children": [
{
"name": "distortion",
"children": [
{"name": "BifocalDistortion", "size": 4461},
{"name": "Distortion", "size": 6314},
{"name": "FisheyeDistortion", "size": 3444}
]
},
{
"name": "encoder",
"children": [
{"name": "ColorEncoder", "size": 3179},
{"name": "Encoder", "size": 4060},
{"name": "PropertyEncoder", "size": 4138},
{"name": "ShapeEncoder", "size": 1690},
{"name": "SizeEncoder", "size": 1830}
]
},
{
"name": "filter",
"children": [
{"name": "FisheyeTreeFilter", "size": 5219},
{"name": "GraphDistanceFilter", "size": 3165},
{"name": "VisibilityFilter", "size": 3509}
]
},
{"name": "IOperator", "size": 1286},
{
"name": "label",
"children": [
{"name": "Labeler", "size": 9956},
{"name": "RadialLabeler", "size": 3899},
{"name": "StackedAreaLabeler", "size": 3202}
]
},
{
"name": "layout",
"children": [
{"name": "AxisLayout", "size": 6725},
{"name": "BundledEdgeRouter", "size": 3727},
{"name": "CircleLayout", "size": 9317},
{"name": "CirclePackingLayout", "size": 12003},
{"name": "DendrogramLayout", "size": 4853},
{"name": "ForceDirectedLayout", "size": 8411},
{"name": "IcicleTreeLayout", "size": 4864},
{"name": "IndentedTreeLayout", "size": 3174},
{"name": "Layout", "size": 7881},
{"name": "NodeLinkTreeLayout", "size": 12870},
{"name": "PieLayout", "size": 2728},
{"name": "RadialTreeLayout", "size": 12348},
{"name": "RandomLayout", "size": 870},
{"name": "StackedAreaLayout", "size": 9121},
{"name": "TreeMapLayout", "size": 9191}
]
},
{"name": "Operator", "size": 2490},
{"name": "OperatorList", "size": 5248},
{"name": "OperatorSequence", "size": 4190},
{"name": "OperatorSwitch", "size": 2581},
{"name": "SortOperator", "size": 2023}
]
},
{"name": "Visualization", "size": 16540}
]
}
]
}
回答by user391339
In order to get it to work I had to replace the line
为了让它工作，我不得不更换线路
d3.json("flare.json", function(error, root) {
with
和
d3.json("flare.json", function(root) {
I used my intuition here and I still do not understand how it worked on the example website and not mine, or what the true significance of my change in the code is. If you know how to answer this in a more in-depth fashion, please contribute and I will accept your answer.
我在这里使用了我的直觉，但我仍然不明白它是如何在示例网站上而不是我的网站上工作的，或者我更改代码的真正意义是什么。如果你知道如何更深入地回答这个问题，请贡献，我会接受你的回答。
回答by Elijah
The code is from d3.v3 but it's pointing to d3.v2, which does not use the error call in the d3.json function.
代码来自 d3.v3 但它指向 d3.v2，它不使用 d3.json 函数中的错误调用。
回答by SolessChong
It's because the returned json object is received by the first parameter of the function. It might because of the versions of d3.
这是因为返回的json对象被函数的第一个参数接收。这可能是因为 d3 的版本。
回答by mugume david
Had the same exact error. The solution is pretty simple: You are not providing a JSON object array. You said your JSON begun as follows:
有同样的错误。解决方案非常简单：您没有提供 JSON 对象数组。你说你的 JSON 开始如下：
{ "name": "flare", "children": [ ...
{ "name": "flare", "children": [ ...
Please change so change is begins as follows:
请更改所以更改开始如下：
[{ "name": "flare", "children": [ ...}]
[{ "name": "flare", "children": [ ...}]
That way D3 will be able to locate the "first child"
这样 D3 就能找到“第一个child”
回答by Arifur Rahman Mazumder
<script>
function liveProject() {
var a=200;
this. x=600;
this. y=300;
this. z= function () {
return this.x+this.y;
}
}
var lp=new liveProject();
document.write(lp.z());
</script>
