Compilation errors when drawing piechart using d3.js and TypeScript

Question

I am trying to draw a pie chart using the d3.js and TypeScript library. I have the following code:

"use strict";
module Chart {
  export class chart {

    private chart: d3.Selection<string>;
    private width: number;
    private height: number;
    private radius: number;
    private donutWidth: number;
    private dataset: { label: string, count: number }[];
    private color: d3.scale.Ordinal<string, string>;

    constructor(container: any) {
      this.width = 360;
      this.height = 360;
      this.radius = Math.min(this.width, this.height) / 2;
      this.donutWidth = 75;

      this.dataset = [
        { label: 'Road', count: 5500 },
        { label: 'Bridge', count: 8800 },
        { label: 'Tunnel', count: 225 },
      ];

      this.color = d3.scale.category10();

      this.init(container);

    }

    private init(container) {
      this.chart = d3.select(container).append('svg')
        .attr('width', this.width)
        .attr('height', this.height)
        .append('g')
        .attr('transform', 'translate(' + (this.width / 2) +
        ',' + (this.height / 2) + ')');
    }

    draw() {

      var arc = d3.svg.arc()
        .innerRadius(this.radius - this.donutWidth)  // NEW
        .outerRadius(this.radius);

      var pie = d3.layout.pie()
        .sort(null);

      var path = this.chart.selectAll('path')
        .data(pie(this.dataset.map(function(n) {
          return n.count;
        })))
        .enter()
        .append('path')
        .attr('d', arc)
        .attr('fill', function(d, i) {
          return Math.random();
        });
    }

  }
}

The code does not compile with an error:

 Argument of type 'Arc<Arc>' is not assignable to parameter of type '(datum: Arc<number>, index: number, outerIndex: number) => string | number | boolean'.
>>   Types of parameters 'd' and 'datum' are incompatible.
>>     Type 'Arc' is not assignable to type 'Arc<number>'.
>>       Property 'value' is missing in type 'Arc'.   

A compilation error appears when I try to add an attribute dto each of the elements pathon my svg:

var path = this.chart.selectAll('path')
        .data(pie(this.dataset.map(function(n) {
          return n.count;
        })))
        .enter()
        .append('path')
        .attr('d', arc)
        .attr('fill', function(d, i) {
          return Math.random();
        });

According to the documentation, an arc is "both an object and a function." and I see that I can access it by calling arc(datum[, index])just using hardcoding arc[0]. When I do this, my compilation error disappears, but the attribute of deach element pathin svg is missing, and I end with svg like:

    <svg height="360" width="360">
      <g transform="translate(180,180)">
         <path fill="0.35327279710072423"></path>
         <path fill="0.6333000506884181"></path>
         <path fill="0.9358429045830001"></path>
      </g>
    </svg>

I had code working as pure JavaScript with no problems.

Answer 1

.attr('d', arc)   

.attr('d', <any>arc)  

, ... , .

, .data number TypeScript , .attr , arc.

Answer 2

<any> , , . d3.d.ts Arc, , :

function draw() {

    let arc = d3.svg.arc<d3.layout.pie.Arc<number>>()
        .innerRadius(this.radius - this.donutWidth)
        .outerRadius(this.radius);

    let pie = d3.layout.pie().sort(null);

    let tfx = (d: d3.layout.pie.Arc<number>): string => `translate(${arc.centroid(d)})`);

    // create a group for the pie chart
    let g = this.chart.selectAll('g')
        .data(pie(this.dataset.map(n => n.count)))
        .enter().append('g');

    // add pie sections
    g.append('path').attr('d', arc);

    // add labels
    g.append('text').attr('transform', tfx).text(d => d.data.label);
}

, , Typescript. , d3.svg.arc<T>(): Arc<T>, arc.

Update

, data . , ( , n => n.count d => d.data.label), . any, .. (n: any) => n.count. , n count. , data :

interface Datum {
    label: string;
    count: number;
}

function draw() {

    // specify Datum as shape of data
    let arc = d3.svg.arc<d3.layout.pie.Arc<Datum>>()
        .innerRadius(this.radius - this.donutWidth)
        .outerRadius(this.radius);

    // notice accessor receives d of type Datum
    let pie = d3.layout.pie<Datum>().sort(null).value((d: Datum):number => d.count);

    // note input to all .attr() and .text() functions
    // will be of type d3.layout.pie.Arc<Datum>
    let tfx  = (d: d3.layout.pie.Arc<Datum>): string => `translate(${arc.centroid(d)})`;
    let text = (d: d3.layout.pie.Arc<Datum>): string => d.data.category;

    // create a group for the pie chart
    let g = this.chart.selectAll('g')
        .data(pie(data))
        .enter().append('g');

    // add pie sections
    g.append('path').attr('d', arc);

    // add labels
    g.append('text').attr('transform', tfx).text(text);
}

any. , Datum . , , Datum , .