Angular-Google-Charts

A wrapper for the Google Charts library written in Angular.

Setup

Installation

To use Angular-Google-Charts in your project, install the package with npm by calling

npm install angular-google-charts

This will add the package to your package.json and install the required dependencies.

Importing

Import the GoogleChartsModule in your app.module.ts:

import { GoogleChartsModule } from 'angular-google-charts';

@NgModule({
  ...
  imports: [
    ...
    GoogleChartsModule,
    ...
  ],
  ...
})
export class AppModule {}

This will allow you to use all of the features provided by this library.

Configuring

For some use cases, it might be necessary to use some different config options than the default values.

All config options for Angular Google Charts are provided through a config object, which can be passed to the library by importing the GoogleChartsModule using its forRoot method or by providing the GOOGLE_CHARTS_LAZY_CONFIG injection token with an Observable<GoogleChartsConfig> value.

Using forRoot

Here you will pass the options that are passed to the google.charts.load method in the normal JavaScript library. For instance, to change the version

GoogleChartsModule.forRoot({ version: 'chart-version' }),

Another example, to specify the Google Maps API key, or any other Settings:

GoogleChartsModule.forRoot({ mapsApiKey: '<your Google Maps API Key here>' }),

Using lazy loading

Option #1

// Provide an observable through a service that fetches your chart configurations

@Injectable()
export class GoogleChartsConfigService {
  private configSubject = new ReplaySubject<GoogleChartsConfig>(1);
  readonly config$ = this.configSubject.asObservable();

  constructor(private http: HttpClient) {}

  loadLazyConfigValues(): void {
    this.http.post('https://special.config.api.com/getchartsconfig', {})
      .pipe(take(1))
      .subscribe(config => this.configSubject.next(config));
  }
}

// Factory function that provides the config$ observable from your GoogleChartsConfigService
export function googleChartsConfigFactory(configService: GoogleChartsConfigService): Observable<GoogleChartsConfig> {
  return configService.config$;
}

@NgModule({
  ...
  providers: [
    GoogleChartsConfigService,
    {provide: GOOGLE_CHARTS_LAZY_CONFIG, useFactory: googleChartsConfigFactory, deps: [GoogleChartsConfigService]}
  ]
})
export class AppModule {}

Option #2

// Use a global subject (whether this violates best practices in your case is up to you).
// This is just to point out a more simple way of achieving a lazy-loaded config.
export const googleChartsConfigSubject = new ReplaySubject<GoogleChartsConfig>(1);

// Call this from anywhere you want
googleChartsConfigSubject.next(config);

// Your app.module
@NgModule({
  ...
  providers: [
    {provide: GOOGLE_CHARTS_LAZY_CONFIG, useValue: googleChartsConfigSubject.asObservable()}
  ]
})
export class AppModule {}

NOTE

• You can provide options through the forRoot function OR the GOOGLE_CHARTS_LAZY_CONFIG token. You cannot use them interchangeably.
• If you provide a lazy-loaded config object then the charts will not render until the observable has a value for the subscriber.

Charts

The easiest way to create a chart is using the GoogleChartComponent.

<google-chart></google-chart>

Using the component, it is possible to create every chart in the Google Charts library. It has a few important input properties, which are explained below.

Type

<google-chart [type]="myType"></google-chart>

The type of chart you want to create. Must be of type ChartType. Check this file for a list of the supported types

To see examples for all chart types and more information, visit the google chart gallery.

Data

<google-chart [data]="myData"></google-chart>

The data property expects an array of a certain shape, which depends on the chart type. Some chart types even support different data formats depending on the mode.

Example with a chart that expects two-dimensional arrays:

myData = [
  ['London', 8136000],
  ['New York', 8538000],
  ['Paris', 2244000],
  ['Berlin', 3470000],
  ['Kairo', 19500000],
  ...
];

The data object can also include formatters for the given data. To use these, pass an object of type { v: any, f: string } as the data values in the inner array. The property v should contain the real value, and the property f the formatted value.

Formatters can also be passed as a separate input property, see Formatters;

myData = [
  ['London', {v: 8136000, f: '8,1360'}],
  ['New York', {v: 8538000, f: '8,530'}],
  ...
];

For further information, please see the official documentation on ArrayToDataTable, which is the function used internally.

Columns

<google-chart [columns]="chartColumns"></google-chart>

The columns property expects an array describing the columns chart data array. The number of entries must match the length of the inner array passed in the data property. Some charts don't require columns. Whether your chart requires it can be check in the official documentation.

Continuing with the simple two-dimensional example:

chartColumns = ['City', 'Inhabitants'];

For more complex formats an array of objects can be passed. For instance, the GeoChart in markers mode expects 4 columns of type number:

chartColumns = [
  { type: 'number', role: 'latitude' },
  { type: 'number', role: 'longitude' },
  { type: 'number', role: 'markerColor' },
  { type: 'number', role: 'markerSize' }
];

Title

<google-chart [title]="myTitle"></google-chart>

The title property is optional and provided for convenience. It can also be included in the options property.

Width

<google-chart [width]="myWidth"></google-chart>

The width property is optional and allows to set the width of the chart. The number provided will be converted to a pixel value. The default is undefined, which makes the chart figure out its width by itself. You can also set the width using CSS, which has the advantage of allowing % values instead of only pixels. For more information on that, see dynamic resize.

Height

<google-chart [height]="myHeight"></google-chart>

The height property is optional and allows to set the height of the chart. The number provided will be converted to a pixel value. The default is undefined, which makes the chart figure out its height by itself. You can also set the height using CSS, which has the advantage of allowing % values instead of only pixels. For more information on that, see dynamic resize.

Options

<google-chart [options]="myOptions"></google-chart>

The options property is optional and allows to customize the chart to a great extent. How and what you can customize depends on the type of chart. For more information, please see the google documentation.

// example
myOptions = {
  colors: ['#e0440e', '#e6693e', '#ec8f6e', '#f3b49f', '#f6c7b6'],
  is3D: true
};

Formatters

<google-chart [formatters]="myFormatters"></google-chart>

The formatter property is optional and allows to format the chart data. It requires an array of objects containing a formatter and an index.

For more information and all formatter types, please refer to the documentation.

// Formats the column with the index 1 and 3 to Date(long)
myFormatters = [
  {
    formatter: new google.visualization.DateFormat({ formatType: 'long' }),
    colIndex: 1
  },
  {
    formatter: new google.visualization.DateFormat({ formatType: 'long' }),
    colIndex: 3
  }
];

Note: When you get the error "google is not defined" whilst using the formatter in your component, you probably didn't load the google charts script. Please read the chapter on using the ScriptLoaderService.

Dynamic Resize

<google-chart [dynamicResize]="dynamicResize"></google-chart>

The dynamicResize property is optional and makes your chart redraw every time the window is resized. Defaults to false and should only be used when setting the width or height of the chart to a percentage value. Otherwise, the chart gets redrawn unnecessary and therefore slows down the site.

Styling

<google-chart style="width: 100%;"></google-chart>

Most CSS properties should work exactly as you would expect them to. If you want to have the chart full-width for example, set the width to 100%.

Events

The GoogleChartComponent provides bindings for the most common Google Chart events.

Ready

The ready event is emitted as soon as the chart got drawn and after every subsequent redraw.

<google-chart (ready)="onReady($event)"></google-chart>

The event is of type ChartReadyEvent.

Error

The error event is emitted when an internal error occurs. However, since the newer versions of google-charts, most errors are displayed in the chart HTML as well. It can be bound to like this:

<google-chart (error)="onError($event)"></google-chart>

The event is of type ChartErrorEvent.

Select

The select event is emitted when an element in the chart gets selected.

<google-chart (select)="onSelect($event)"></google-chart>

The event of type ChartSelectionChangedEvent containing an array of selected values.

Mouseover

The mouseover event fires when the mouse hovers over one of the charts elements (i. e. a bar in a bar chart or a segment in a pie chart).

<google-chart (mouseover)="OnMouseOver($event)"></google-chart>

The event is of type ChartMouseOverEvent, where column is the index of the hovered column and row is the index of the hovered row.

Mouseleave

The mouseleave event fires when the mouse stops hovering one of the charts elements (i. e. a bar in a bar chart or a segment in a pie chart).

<google-chart (mouseleave)="onMouseLeave($event)"></google-chart>

The event is of type ChartMouseLeaveEvent, where column is the index of the no-longer hovered column and row is the index of the no-longer hovered row.

Controls and Dashboards

Google Charts supports combining multiple charts into dashboards and giving users controls to manipulate what data they show, see their documentation. Using this library, dashboards can be created easily.

A dashboard component can be instantiated, which can contain child controls and charts. Every control must specify one or more charts they are controlling via their for property. It accepts a single chart as well as an array of charts, and one chart can be controlled by multiple controls.

<dashboard [columns]="dashboardColumns" [data]="dashboardData">
  <control-wrapper [for]="dashboardChart" [type]="controlFilterType" [options]="controlOptions"></control-wrapper>
  <google-chart #dashboardChart type="PieChart" [width]="300" [height]="300"> </google-chart>
</dashboard>

When creating dashboards, the charts themselves are not responsible for drawing, which means their columns, data, and (optional) formatter properties are unused. Instead, the dashboard is responsible for drawing. It therefore accepts data in the same format as charts do through the columns, data, and formatter properties.

Note that charts in a dashboard will not be visible if they are not referenced in at least one control.

Editing Charts

Google Charts comes with a full-fledged chart editor, allowing users to configure charts the way they want.

Angular-Google-Charts includes a component wrapping the native ChartEditor, the ChartEditorComponent. It has to be instantiated in HTML and can be used to edit charts by calling its editChart method.

<!--my.component.html-->
<chart-editor></chart-editor>

<google-chart #editable></google-chart>
<button (click)="editChart(editable)">Edit</button>

// my.component.ts
class MyComp {
  @ViewChild(ChartEditorComponent)
  public readonly editor: ChartEditorComponent;

  public editChart(chart: ChartBase) {
    this.editor
      .editChart(chart)
      .afterClosed()
      .subscribe(result => {
        if (result) {
          // Saved
        } else {
          // Cancelled
        }
      });
  }
}

editChart returns a handle to the open dialog which can be used to close the edit dialog.

Note that only one chart can be edited by a chart editor at a time.

Advanced

Accessing the chart wrapper directly

I case you don't need any of the special features the GoogleChartsComponent provides, the ChartWrapperComponent can be used. It is a direct wrapper of the ChartWrapper..

<chart-wrapper [specs]="chartWrapperSpecs"></chart-wrapper>

The ChartWrapperComponent should be used if you need fine-grained control over the data you are providing or you want to use e.g. the query feature that Google Charts provides, which is not supported using the GoogleChartComponent.

Using the ScriptLoaderService

If a specific chart is created a lot in your application, you may want to create custom components.

When doing so, you need to load the chart packages by yourself. The ScriptLoaderService provides a few methods helping with this.

class MyComponent {
  private readonly chartPackage = getPackageForChart(ChartType.BarChart);

  @ViewChild('container', { read: ElementRef })
  private containerEl: ElementRef<HTMLElement>;

  constructor(private loaderService: ScriptLoaderService) {}

  ngOnInit() {
    this.loaderService.loadChartPackages(this.chartPackage).subscribe(() => {
      // Start creating your chart now
      const char = new google.visualization.BarChart(this.containerEl.nativeElement);
    });
  }
}

The loadChartPackages method can also be called without any parameters. This way, only the default google charts packages will be loaded. These include the namespaces google.charts and google.visualization, but no charts.

Preloading the Google Charts script

If the existence of charts is crucial to your application, you may want to decrease the time it takes until the first chart becomes visible. This can be achieved by loading the Google Charts script concurrently with the rest of the application. In the playground application, this reduces the time until the first chart appears by roughly 20%, which means for example about 4 seconds when using the "Slow 3G" profile in Chrome DevTools.

To achieve this, two scripts have to be added to the index.html file in your apps' root folder. The first one loads the generic Google Charts script, the second one the version-specific parts of the library needed to load charts.

In the code below, <chart_version> has to be replaced with the exact of the Google Charts library that you want to use and must match the version you use when importing the GoogleChartsModule.

The only exception to this is version 46. All minor versions of Google Charts v46 require the loader to be of version 46.2.

<script type="text/javascript" src="https://www.gstatic.com/charts/loader.js" async></script>
<script type="text/javascript" src="https://www.gstatic.com/charts/<chart_version>/loader.js" async></script>

Please note that this can increase the time it takes until Angular is fully loaded. I suggest doing some benchmarks with your specific application before deploying this to production.

License

This project is provided under the MIT license.