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我正在使用Recharts库构建图表库。

这些是我正在处理的文件

数据夹具是charts.js

const charts = [
  {name: 'Page A', uv: 4000, pv: 2400, amt: 2400},
  {name: 'Page B', uv: 3000, pv: 1398, amt: 2210},
  {name: 'Page C', uv: 2000, pv: 9800, amt: 2290},
  {name: 'Page D', uv: 2780, pv: 3908, amt: 2000},
  {name: 'Page E', uv: 1890, pv: 4800, amt: 2181},
  {name: 'Page F', uv: 2390, pv: 3800, amt: 2500},
  {name: 'Page G', uv: 3490, pv: 4300, amt: 2100},
];

export default charts;

数据与其他数据一起正确导入我的商店

然后我有我的ChartsGrid.js错误来自哪里

import React from 'react';
import Chart from './Chart';

export default class ChartsGrid extends React.Component{
  render() {
    return (
      <div className="grid">
        {this.props.charts.map((chart, i) => <Chart {...this.props} key={i} i={i} chart={chart} />)}
      </div>
    )
  }
};

在这里我的图表组件从 recharts 库中导入模块

import React from 'react';
import { Link } from 'react-router';
import { ResponsiveContainer, LineChart, Line, XAxis, YAxis, ReferenceLine,
  ReferenceDot, Tooltip, CartesianGrid, Legend, Brush } from 'recharts';

export default class Chart extends React.Component {
  render () {
    const { chart, i} = this.props;
    return (
        <LineChart width={600} height={300} data={charts}
            margin={{top: 5, right: 30, left: 20, bottom: 5}}>
       <XAxis dataKey="name"/>
       <YAxis/>
       <CartesianGrid strokeDasharray="3 3"/>
       <Tooltip/>
       <Legend />
       <Line type="monotone" dataKey="pv" stroke="#8884d8" activeDot={{r: 8}}/>
       <Line type="monotone" dataKey="uv" stroke="#82ca9d" />
      </LineChart>
    );
  }
};

为什么会抛出此错误 TypeError: Cannot read property 'map' of undefined ？什么实际上是未定义的？

4

5 回答 5

1

Looks like you have not imported the charts.js file before using the charts array.

You could import the charts.js file where you use the ChartsGrid component and pass charts as a prop:

import charts from './charts'
...
<ChartsGrid charts={charts} />

Or, you could use the charts object directly in ChartsGrid.js instead of this.props.

import charts from './charts'

export default class ChartsGrid extends React.Component{
  render() {
    return (
      <div className="grid">
        {charts.map((chart, i) => 
          <Chart {...this.props} key={i} i={i} chart={chart} />)}
      </div>
    )
  }
}

Note charts.map instead of this.props.charts.map because charts is directly imported in the file instead of being passed as a prop to the component (as in the 1st solution).

于 2016-11-12T20:05:03.327 回答
0

将 ChartsGrid.js 更改为 

import React from 'react';
import Chart from './Chart';

export default class ChartsGrid extends React.Component{
  render() {
   if(this.props.charts){
     return (
       <div className="grid">
         {this.props.charts.map((chart, i) => <Chart {...this.props} key={i} i={i} chart={chart} />)}
       </div>
      )
    }
    else return(
       <div className="grid"></div>
    )
  }
};
于 2016-11-12T19:57:23.453 回答
0

您缺少父组件

父.js

import ChartsGrid from './ChartsGrid';

const charts = [
  {name: 'Page A', uv: 4000, pv: 2400, amt: 2400},
  {name: 'Page B', uv: 3000, pv: 1398, amt: 2210},
  {name: 'Page C', uv: 2000, pv: 9800, amt: 2290},
];

class ParentComponent extends React.Component{
    render(){
        return(<ChartsGrid charts={charts}/>)
    }
}
于 2016-11-12T20:00:47.390 回答
0

我认为您需要调用“ChartsGrid”标签并在其中传递一个名为“charts”的属性。喜欢：

<ChartsGrid charts={}...>

我无法找到您在哪里使用过“ChartsGrid”标签。

于 2016-11-12T19:56:22.233 回答
0

使用反应开发工具来验证this.props.charts是否以数组的形式进入。

如果您想要更好的答案，请包含传递charts给的组件代码ChartsGrid

于 2016-11-12T19:53:23.017 回答