Chartjs-plugin-datalabels: Import error: "Module 'chartjs-plugin-datalabels/types/index' has no default export."

[pjc2007]

Trying out Chart.js, and have been told I need to use the chartjs-plugin-datalabels to be able to write the percentage text on the piew pieces.

I installed and imported the chartjs-plugin-datalabels as per the documentation into my Angular 7 project (actually Ionic 4, which uses Angular 7), but vscode reports the following error on the import...

Module '"../../../../node_modules/chartjs-plugin-datalabels/types"' has no exported member 'ChartDataLabels'.ts(2

I have the following versions
"chart.js": "^2.8.0", "chartjs-plugin-datalabels": "^0.6.0",

If I go to the node_moduleschartjs-plugin-datalabels\types\index.d.ts file, I also see a similar error here for the line

declare module 'chart.js

Invalid module name in augmentation. Module 'chart.js' resolves to an untyped module at 'd:/dev/ionic/chartjstest/node_modules/chart.js/dist/Chart.js', which cannot be augmented.ts

If I proceed, and try to run, I then get the compile error

[ng] ERROR in node_modules/chartjs-plugin-datalabels/types/index.d.ts(5,16): error TS2665: Invalid module name in augmentation. Module 'chart.js' resolves to an untyped module at 'D:/dev/ionic/chartjstest/node_modules/chart.js/dist/Chart.js', which cannot be augmented. [ng] src/app/home/pie-graph/pie-graph.component.ts(3,10): error TS2305: Module '"D:/dev/ionic/chartjstest/node_modules/chartjs-plugin-datalabels/types/index"' has no exported member 'ChartDataLabels'.

[danielwstrimpel]

You can fix this issue with installing the types for Chart.js via npm install @types/chart.js

[pjc2007]

@danielwstrimpel I installed this, but now get further errors as well as the original.

So I still have the error at the import...
"@types/chart.js": "^2.7.50",

But I still get the import error...

.

And the following compile error..

[ng] ERROR in src/app/home/line-graph/line-graph.component.ts(55,17): error TS2559: Type 'false' has no properties in common with type 'ChartLegendOptions'.
[ng] src/app/home/pie-graph/pie-graph.component.ts(3,10): error TS2305: Module '"D:/dev/ionic/chartjstest/node_modules/chartjs-plugin-datalabels/types/index"' has no exported member 'ChartDataLabels'.
[ng]

[danielwstrimpel]

Those last two errors listed look like problems in your usage.

The false error looks like you are setting a property wrong. Double check your usage of the library there as the types aren't matching up.

For the second one, you should import the library like import * as ChartDataLabels from 'chartjs-plugin-datalabels';. The library isn't exporting things like you are probably used to in Typescript.

[pjc2007]

@danielwstrimpel - yes some of those errors are coming from another (test) component where I was trying the Chart as a line graph. Funny everything I set in there worked, and now it is telling me some of the options are not valid...

I wonder if the typedef is up to date with the library?

At any rate, I commented out these, so can just look at the error we are concerned with here.

So now, I still have the import error, and now the only compile error is

[ng] ERROR in src/app/home/pie-graph/pie-graph.component.ts(3,10): error TS2305: Module '"D:/dev/ionic/chartjstest/node_modules/chartjs-plugin-datalabels/types/index"' has no exported member 'ChartDataLabels'.
[ng] 

Yes, I certainly want to know how to import this into a TypeScript project (if that is different for some reason)

[simonbrunel]

@pjc2007 How do you import this plugin? can you share the code of your project so it will be easier to debug?

[pjc2007]

@simonbrunel - yes for sure, I'll include all my component code here. This is just a test app for my to try out chart.js, so is a little adhoc and untidy with me trying stuff out. But all has worked so far except for using this plugin

I created a new Ionic 4 blank application, and have installed the following...

dependencies:

"chart.js": "^2.8.0",
"chartjs-plugin-datalabels": "^0.6.0",

devDependencies

"@types/chart.js": "^2.7.50",

And the component code...

import { Component, OnInit, ViewChild } from '@angular/core';
import { Chart, ChartOptions } from 'chart.js';
import { ChartDataLabels } from 'chartjs-plugin-datalabels';
//import 'chartjs-plugin-datalabels';

@Component({
  selector: 'app-pie-graph',
  templateUrl: './pie-graph.component.html',
  styleUrls: ['./pie-graph.component.scss'],
})
export class PieGraphComponent implements OnInit {
  @ViewChild('mygraph') private chartRef;
  chart: Chart;

  chartLabels: any;

  data: any;
  constructor() {
    //this.chartLabels = ChartDataLabels;
    Chart.plugins.unregister(ChartDataLabels);
   }

  public updateClick(evt) : void {
    try {
      let activePoints = this.chart.getElementsAtEvent(evt);
      let i = 0;  

      this.data.datasets[0].data[0] = 44;
      this.chart.update();
    } catch (error) {
      alert(error);
    }

  }

  public ngOnInit() : void {
    this.data = {
      datasets: [{
        data: [10, 20, 30, 50],
        backgroundColor: [
          'green',
          'rgba(54, 162, 235, 0.2)',
          'rgba(255, 206, 86, 0.2)',
          'rgba(75, 192, 192, 0.2)',
          'rgba(153, 102, 255, 0.2)',
          'rgba(255, 159, 64, 0.2)'
        ],
      }],

      // These labels appear in the legend and in the tooltips when hovering different arcs
      labels: [
        'Red',
        'Yellow',
        'Blue',
        'another'
      ]
    };

    let options : ChartOptions = {
      responsive: true,
      maintainAspectRatio: false,
      legend: {
        position: 'bottom',
        labels: {
          boxWidth: 20
        }
      },
      tooltips: {
        enabled: false
      },
      plugins: {
        datalabels: {
          formatter: (value, ctx) => {
            return 'hello';
            let sum = 0;
            let dataArr = ctx.chart.data.datasets[0].data;
            // dataArr.map()
            // dataArr.map((data, i, array) => {
            //   sum += data;
            // });
            let percentage = (value * 100 / sum).toFixed(2) + "%";
            return percentage;


          },
          color: 'black',
        }
      }
    };
    this.chart = new Chart(this.chartRef.nativeElement, { 
      plugins: [ChartDataLabels],
      type: 'pie',
      data: this.data,
      options: options
    });
  }
}

I can share the whole project if that is of any help

[simonbrunel]

@pjc2007 I installed and imported the chartjs-plugin-datalabels as per the documentation...

Per the documentation:

import ChartDataLabels from 'chartjs-plugin-datalabels';

[pjc2007]

@simonbrunel - oh ok, yes I did add the braces when I I got the error it without them.

I changed back so now I have...

IF we required, whole repo is at https://github.com/pjc2007/testChartjs

[simonbrunel]

I think that's because the TS declaration doesn't export the plugin, so import ChartDataLabels from 'chartjs-plugin-datalabels'; doesn't work with TS. I will need to investigate what's the best way to fix it but in the meantime, you can import 'chartjs-plugin-datalabels'; (the old way), meaning that you will not be able to register the plugin per chart (neither unregister it globally).

[pjc2007]

@simonbrunel - ok thanks for that!

I tried the import 'chartjs-plugin-datalabels'; and removed the plugin stuff..

constructor() {
    //this.chartLabels = ChartDataLabels;
    // Chart.plugins.unregister(ChartDataLabels);
   }

 this.chart = new Chart(this.chartRef.nativeElement, { 
      //plugins: [ChartDataLabels],
      type: 'pie',
      data: this.data,
      options: options
    });
....

and now at least my formatter() is now called.

I now have

 let options : ChartOptions = {
      responsive: true,
      maintainAspectRatio: false,
      legend: {
        position: 'bottom',
        labels: {
          boxWidth: 20
        }
      },
      tooltips: {
        enabled: false
      },
      plugins: {
        datalabels: {
          formatter: (value, ctx) => {            
            let dataArr = ctx.chart.data.datasets[0].data;
            let total = sum(dataArr);     // sum from lodash        
            let percentage = (value * 100 / total).toFixed(2) + "%";
            return percentage;
          },
          color: 'black',
        }
      }
    };
    this.chart = new Chart(this.chartRef.nativeElement, {       
      type: 'pie',
      data: this.data,
      options: options
    });
  }

So I can now get my percentage labels!

I am sure I had tried the import 'chartjs-plugin-datalabels'; but I never had the formatter() called, but certainly seems to work now

[danielwstrimpel]

@simonbrunel the correct way to import the library and get a reference to the output in Typescript is import * as ChartDataLabels from 'chartjs-plugin-datalabels'; (based on how the library is currently being exported)

[pjc2007]

@danielwstrimpel - I tried this and seems to work 100%! Thanks for that.

Wonder if that could be put in the doco for other Angular / TypeScript users (there are a lot of people in this category that use this library)?

So, I can now type everything which helps a lot with getting setup correct.

So, the full code is now as follows.

import { Component, OnInit, ViewChild } from '@angular/core';
import { Chart, ChartOptions, ChartData } from 'chart.js';
import * as ChartDataLabels  from 'chartjs-plugin-datalabels';
import { sum } from 'lodash';

@Component({
  selector: 'app-pie-graph',
  templateUrl: './pie-graph.component.html',
  styleUrls: ['./pie-graph.component.scss'],
})
export class PieGraphComponent implements OnInit {
  @ViewChild('mygraph') private chartRef;
  chart: Chart;
  data: ChartData;
  constructor() {
    Chart.plugins.unregister(ChartDataLabels);
   }

  public updateClick(evt) : void {
    try {
      let activePoints = this.chart.getElementsAtEvent(evt);
      let i = 0;  

      this.data.datasets[0].data[0] = 44;
      this.chart.update();
    } catch (error) {
      alert(error);
    }

  }

  public ngOnInit() : void {
    this.data = {
      datasets: [{
        data: [10, 20, 30, 50],
        backgroundColor: [
          'green',
          'rgba(54, 162, 235, 0.2)',
          'rgba(255, 206, 86, 0.2)',
          'rgba(75, 192, 192, 0.2)',
          'rgba(153, 102, 255, 0.2)',
          'rgba(255, 159, 64, 0.2)'
        ],
      }],

      // These labels appear in the legend and in the tooltips when hovering different arcs
      labels: [
        'Red',
        'Yellow',
        'Blue',
        'another'
      ]
    };

    let options : ChartOptions = {
      responsive: true,
      maintainAspectRatio: false,
      legend: {
        position: 'bottom',
        labels: {
          boxWidth: 20
        }
      },
      tooltips: {
        enabled: false
      },
      plugins: {
        datalabels: {
          formatter: (value, ctx) => {
            let dataArr = ctx.chart.data.datasets[0].data;
            let total = sum(dataArr);
            let percentage = (value * 100 / total).toFixed(2) + "%";
            return percentage;
          },
          color: 'black',
        }
      }
    };
    this.chart = new Chart(this.chartRef.nativeElement, { 
      plugins: [ChartDataLabels],
      type: 'pie',
      data: this.data,
      options: options
    });
  }
}

[simonbrunel]

@pjc2007 @danielwstrimpel I'm not sure why * as ... works in TS but it's not the way we want to promote for importing this plugin. It's better to fix the TS declaration instead of documenting different methods for ES6 or TS, something like this in types/index.d.ts:

declare var plugin: object;

export default plugin;

So users can import using:

import ChartDataLabels from 'chartjs-plugin-datalabels';

Note that this change would break import * as ChartDataLabels ...

[pjc2007]

@simonbrunel Imports are the one thing that always "get me" in TypeScript , and I can spend hours trying to work it out when they are not "standard", so yes I agree with you.

The imports syntax from the chart.js is how most seem to be, i.e.

import { Chart, ChartOptions, ChartData } from 'chart.js';

So you can import individual classes (listing each inside of the { })

Also in some cases, from what I understand, this can also have the potential to help with "tree shaking" i.e. not having to import everything.

[lenichols]

+1

[simonbrunel]

This is fixed by 92771df1588e80df1d5a70cbd8d53557222c3205 and will be released in v0.7.0. The proper way to include this plugin in TS will be:

import ChartDataLabels from 'chartjs-plugin-datalabels';

// or

import { default as ChartDataLabels  } from 'chartjs-plugin-datalabels';

[sandyeveliz]

Adding this as @pjc2007 says work out for me in Dev Builds

devDependencies

"@types/chart.js": "^2.7.50",

[geyuqiu]

Temporarily I resolved the error by changing the type of chart to any instead of Chart.

[DnyaneshBaravkar]

You can fix this issue with installing the types for Chart.js via npm install @types/chart.js

Thanks its working...

[simonbrunel]

Released in version 0.7.0.

[Cimmeron]

I just installed this and using

import ChartDataLabels from 'chartjs-plugin-datalabels';
or
import { default as ChartDataLabels } from 'chartjs-plugin-datalabels';

I get the error

ERROR in node_modules/chartjs-plugin-datalabels/types/index.d.ts(3,16): error TS2665: Invalid module name in augmentation. Module 'chart.js' resolves to an untyped module at 'c:/SVN_repos/devel opment/src/dms_client/trunk/node_modules/chart.js/dist/Chart.js', which cannot be augmented.

The only import that works is import 'chartjs-plugin-datalabels';

[simonbrunel]

@Cimmeron you need to install @types/chart.js as suggested in other comments.

[quyennguyenvan]

i dont know, until now, i still can't using this plugin when import

error response
ERROR in src/app/dashboard/inventory/inventory.component.ts(14,45): error TS2307: Cannot find module 'chartjs-plugin-datalabels'.

[dssagar93]

When I had installed @types/chart.js, it gave me another error for

font: {
            weight: '500'
}

inside
datalabels

I had to comment this one out and also I commented
weight?: 'normal' | 'bold' | 'bolder' | 'lighter' | number in node_moduleschartjs-plugin-datalabels\typesoptions.d.ts
and the error was gone. A temporary fix maybe.

[HamzaNb]

npm i chartjs-plugin-datalabels

[hunterwick]

Here is a solution that will always work:

You will need @types/chartjs
add any behind each error that the compiler will throw

Importing
import * as ChartDataLabels from 'chartjs-plugin-datalabels'; Chart.plugins.unregister(ChartDataLabels as any);

Some example inside the code
const placeHolder = document.getElementById('chartPlaceHolder') as HTMLCanvasElement;

this.subChart = new Chart(placeHolder as HTMLCanvasElement, {
type: 'doughnut',
plugins: [ChartDataLabels as any],
data: chartData.data,
options: chartData.options as any
});

You can put as any if you dont know the required type
Else put the object type directly