"I am looking to retrieve the properties of an object that belongs to the EChartsOption type in TypeScript when working with Angular and ECharts. How

Currently, I am exploring how to access a property of an EChartOptions object in Angular 16.0.2, which may be undefined as I am still new to TypeScript.

List of npm packages:

eapp/src$ npm list
<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="8ce9f4ede1fce0e9edfcfcccbca2bca2bc">[email protected]</a> /home/martin/development/node-level-resource-monitoring/webapp/exampleapp
├── @angular-devkit/<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="6604130f0a024b070801130a071426575048564854">[email protected]</a>
...
... (omitted for brevity)

The code base for my component:

import { Component } from '@angular/core';
...

// Component code omitted

...

I am attempting to create a function that accesses the data property using the ?. operator, but it is not working as expected. The interpreter displays the following error message:

Object is possibly 'undefined'.ts(2532) Element implicitly has an 'any' type because expression of type '0' can't be used to index type 'SeriesOption$1 | SeriesOption$1[]'. Property '0' does not exist on type 'SeriesOption$1 | SeriesOption$1[]'.

The code snippet causing the issue:

  getMaxSeriesDataVal(){
    let newVar = 0;
    for (let i = 0; i < 3; i++){
      console.log(this.options?.series[0]?.data[0]) //DOESN'T WORK!!!
    } 
  }

Is there a simpler solution to this problem or should I reconsider my approach when working with Angular components and echart properties?

angulartypescriptechartsapache-echartsngx-echarts

Answer №1

It is recommended to store the data for your chart in a variable and then pass that variable to the chart. This way, you can easily manipulate or iterate through the data as needed within your function. If any changes are made to the data, remember to rebuild the chart to reflect those changes accurately.

Answer №2

In a recent discussion by @s_erfani, it was highlighted that incorporating additional variables to store data has made accessing and iterating over the data much simpler.

import { Component } from '@angular/core';
import { ECharts, EChartsOption } from 'echarts';


@Component({
  selector: 'app-nodelevelvisual2-d',
  templateUrl: './nodelevelvisual2-d.component.html',
  styleUrls: ['./nodelevelvisual2-d.component.css'],
})
export class Nodelevelvisual2DComponent {

  mergeOptions: EChartsOption;
  
  seriesName : string = "heatmap-example";
  dataArr : Array<Array<number>> = [[0,0, 0],[1,1,55],[0,2,0],[0,3,33], [15,99,66],[2,3,2]]
  days : Array<string> = ["monday", "thusday", "wensday", "thursday", "friday"];
  hours : Array<string> = ["0 am", "1 am", "2 am", "3 am", "4 am", "5 am", "6 am", "7 am", "8 am"];

  constructor() { 
    this.mergeOptions = {};
    
  }

  options: EChartsOption = {
    legend: { } ,
    tooltip: {
      position: 'left'
    },
    grid: {
      height: '40%',
      top: '20%'
    },
    xAxis: {
      type: 'category',
      data: this.hours,
      splitArea: {
        show: true
      }
    },
    yAxis: {
      type: 'category',
      data: this.days,
      splitArea: {
        show: true
      }
    },
    visualMap: {
      min: 0,
      max: 15,
      calculable: true,
      orient: 'horizontal',
      left: 'center',
      bottom: '0%'
    },

    series: [
      {
        name: this.seriesName,
        type: "heatmap",
        data: this.dataArr
      }
    ]
  };

  
  getMaxSeriesDataVal(){
    let currentBiggestNum = 0;
    this.dataArr.forEach(function (valueArr) {
        if( valueArr[2] >= currentBiggestNum ){
          currentBiggestNum = valueArr[2];
        }
    })
    console.log(currentBiggestNum)
  }

}

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