javascript - 无法在 React.js 中导入 d3-queue？尝试导入错误 : 'queue' is not exported from 'd3' (imported as 'd3' )

Question

试图从 https://bl.ocks.org/mbostock/4657115 中获取一个示例使用 React.js。

我收到错误:Attempted import error: 'queue' is not exported from 'd3' (imported as 'd3').

但是在安装 d3-queue 之后，我在我的组件中尝试了以下导入:

import * as d3queue from 'd3-queue';

import {queue} from 'd3-queue';

但都没有解决错误。

我错过了什么？还是我错过了弃用？

我的代码:

import React from 'react';

import * as d3 from 'd3';
import * as d3queue from 'd3-queue';
import * as topojson from 'topojson';

export default class CongressionalDistricts extends React.Component {
  state = {
    usData: null,
    usCongress: null
  }

  componentWillMount() {
    d3.queue()
      .defer(d3.json, "us.json")
      .defer(d3.json, "us_congress_113.json")
      .await((error, usData, usCongress) => {
        this.setState({
          usData,
          usCongress
        });
      })
  }

  componentDidUpdate() {
    const svg = d3.select(this.refs.anchor),
                {width, height} = this.props;

    const projection = d3.geoAlbers()
                      .scale(1280)
                      .translate([width / 2, height / 2]);

    const path = d3.geoPath(projection);

    const us= this.state.usData,
          congress = this.state.usCongress

    svg.append("defs").append("path")
      .attr("id", "land")
      .datum(topojson.feature(us, us.objects.land))
      .attr("d", path);

    svg.append("clipPath")
        .attr("id", "clip-land")
      .append("use")
        .attr("xlink:href", "#land");

    svg.append("g")
        .attr("class", "districts")
        .attr("clip-path", "url(#clip-land)")
      .selectAll("path")
        .data(topojson.feature(congress, congress.objects.districts).features)
      .enter().append("path")
        .attr("d", path)
      .append("title")
        .text(function(d) { return d.id; });

    svg.append("path")
        .attr("class", "district-boundaries")
        .datum(topojson.mesh(congress, congress.objects.districts, function(a, b) { return a !== b && (a.id / 1000 | 0) === (b.id / 1000 | 0); }))
        .attr("d", path);

    svg.append("path")
        .attr("class", "state-boundaries")
        .datum(topojson.mesh(us, us.objects.states, function(a, b) { return a !== b; }))
        .attr("d", path);
  }

  render() {
    const { usData, usCongress } = this.state;

    if (!usData || !usCongress) {
      return null;
    }

    return <g ref="anchor" />
  }
}

Answer 1

如果您使用的是 D3.v5，您在尝试使用 d3.queue() 时会遇到同样的错误，因为它已被 Promise.all() 取代.

这是一个如何使用它的例子:

Promise.all([
        d3.csv('data1.csv'),
        d3.csv('data2.csv')
        ]).then( ([data1, data2]) => {
            // do stuff
            console.log(data1, data2);
        }).catch(err => console.log('Error loading or parsing data.'))

您可以通过在终端上运行以下命令来了解您使用的是哪个版本的 D3:npm list d3。