Question

我正在尝试将一个简单的D3.js条形图添加到Ionic 2项目中。

我导入了d3并安装了类型定义，如下所示：

npm install d3
npm install @types/d3 --save-dev --save-exact

我在页面的TS文件中添加了以下内容：

import * as d3 from 'd3'

运行ionic serve时，它会找到没有问题的定义文件。当我尝试一个简单的图表示例，如下所示，它也没有问题：

var sampleSVG = d3.select("#chart")
    .append("svg")
    .attr("width", 100)
    .attr("height", 100);    

sampleSVG.append("circle")
    .style("stroke", "gray")
    .style("fill", "white")
    .attr("r", 40)
    .attr("cx", 50)
    .attr("cy", 50)
    .on("mouseover", function(){d3.select(this).style("fill", "aliceblue");})
    .on("mouseout", function(){d3.select(this).style("fill", "white");});

但是，当我尝试以下条形图示例（找到here）时，它无法正常工作：

var svg = d3.select("svg"),
    margin = {top: 20, right: 20, bottom: 30, left: 40},
    width = +svg.attr("width") - margin.left - margin.right,
    height = +svg.attr("height") - margin.top - margin.bottom;

var x = d3.scaleBand().rangeRound([0, width]).padding(0.1),
    y = d3.scaleLinear().rangeRound([height, 0]);

var g = svg.append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

d3.tsv("data.tsv", function(d) {
  d.frequency = +d.frequency;
  return d;
}, function(error, data) {
  if (error) throw error;

  x.domain(data.map(function(d) { return d.letter; }));
  y.domain([0, d3.max(data, function(d) { return d.frequency; })]);

  g.append("g")
      .attr("class", "axis axis--x")
      .attr("transform", "translate(0," + height + ")")
      .call(d3.axisBottom(x));

  g.append("g")
      .attr("class", "axis axis--y")
      .call(d3.axisLeft(y).ticks(10, "%"))
    .append("text")
      .attr("transform", "rotate(-90)")
      .attr("y", 6)
      .attr("dy", "0.71em")
      .attr("text-anchor", "end")
      .text("Frequency");

  g.selectAll(".bar")
    .data(data)
    .enter().append("rect")
      .attr("class", "bar")
      .attr("x", function(d) { return x(d.letter); })
      .attr("y", function(d) { return y(d.frequency); })
      .attr("width", x.bandwidth())
      .attr("height", function(d) { return height - y(d.frequency); });
});

我得到一个未定义的打字稿错误列表（即使D3 v4的定义文件已成功导入）：

[11:54:14]  typescript: src/pages/page1/page1.ts, line: 35 
            Property 'frequency' does not exist on type 'DSVRowString'. 

      L34:  d3.tsv("data.tsv", function(d) {
      L35:    d.frequency = +d.frequency;
      L36:    return d;

[11:54:14]  typescript: src/pages/page1/page1.ts, line: 35 
            Property 'frequency' does not exist on type 'DSVRowString'. 

      L34:  d3.tsv("data.tsv", function(d) {
      L35:    d.frequency = +d.frequency;
      L36:    return d;
[11:54:14]  typescript: src/pages/page1/page1.ts, line: 40 

            Property 'letter' does not exist on type 'DSVRowString'. 

      L40:    x.domain(data.map(function(d) { return d.letter; }));
      L41:    y.domain([0, d3.max(data, function(d) { return d.frequency; })]);

[11:54:14]  typescript: src/pages/page1/page1.ts, line: 41 
            The type argument for type parameter 'T' cannot be inferred from the usage. Consider specifying the type 
            arguments explicitly. Type argument candidate 'DSVRowString' is not a valid type argument because it is not 
            a supertype of candidate 'string'. 

      L40:    x.domain(data.map(function(d) { return d.letter; }));
      L41:    y.domain([0, d3.max(data, function(d) { return d.frequency; })]);
[11:54:14]  typescript: src/pages/page1/page1.ts, line: 59 

            Argument of type 'DSVParsedArray<DSVRowString>' is not assignable to parameter of type '(this: BaseType, 
            datum: {}, index: number, groups: ArrayLike<BaseType> | BaseType[]) => {}[]'. Type 
            'DSVParsedArray<DSVRowString>' provides no match for the signature '(this: BaseType, datum: {}, index: 
            number, groups: ArrayLike<BaseType> | BaseType[]): {}[]' 

      L58:  g.selectAll(".bar")
      L59:    .data(data)
      L60:    .enter().append("rect")

[11:54:14]  transpile failed

Answer 1

简短的回答是，您没有在回调中告诉打字稿您的参数的类型。你如何做到这一点通常很棘手，所以我觉得有用的是查看类型文件的单元测试。对于这种情况，请参阅here。未经测试但它最终会看起来像这样：

interface ChartData {
  frequency: string;
  letter: number;      
}

d3.tsv("data.tsv", function(d) {
  let rr: d3Dsv.DSVRowString = d;
  let pr: ChartData;

  pr = {
    frequency: +rr['frequency'],
    letter: rr['letter']
  };

  return pr;
}, function(error, data:Array<ChartData>) {

  ...

}

Answer 2

作为一种解决方法，我在模型文件中使用了declare var d3: any;（在本例中为src/pages/page1/page1.ts）。要使用此方法，我必须在<script src="d3.v3.min.js"></script>中手动插入src/index.html，而不是使用通过Node导入。

＆＃34;属性_在_ type＆＃34;上不存在Ionic 2项目中的D3.js打字稿错误

2 个答案: