angular & "ReferenceError: google is not defined"

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Andrea Buzzi

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Sep 30, 2020, 9:36:10 AM9/30/20
to Google Visualization API

Hello,
due to some missing feature on  "FERNman / angular-google-charts" wrapper (like: role "style"/"annotation") I'm trying to feed the classic "google.charts.load" into a fresh test-ui angular project (v10).

So far I've put in app.component.html:

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

  <body>
   <div id="donutchart" style="width: 900px; height: 500px; border:solid 1px black"></div>
  </body>
</html>

while app.component.ts I've the following:

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

declare var google: any;

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})

export class AppComponent {
  title = 'test-ui';

  drawChart=function() {
  var data = google.visualization.arrayToDataTable([['Task', 'Hours per Day'], ['Work', 11], ['Eat', 2], ['Commute', 2], ['Watch TV', 2], ['Sleep', 7] ]);
  var options = { title: 'My Daily Activities', pieHole: 0.4 };
  var chart = new   google.visualization.PieChart(document.getElementById('donutchart'));
  chart.draw(data, options);
}

ngOnInit() {
  google.charts.load('current', {'packages':['corechart']});
  google.charts.setOnLoadCallback(this.drawChart);
}

}


Unfortunately this generate a "ERROR ReferenceError: google is not defined"...

Any tip to make this sample graph working in a angular environment ?

Thx in advance for any suggestion/hint/example!

Andrea


Daniel LaLiberte

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Sep 30, 2020, 10:58:29 AM9/30/20
to Google Visualization API
Hi Andrea,

That kind of error, "google is not defined", means that at the time you use the google symbol, the loader has not finished loading.  I suspect the problem might be that ngOnInit is called before the component html has been defined and/or used, so the loader has not necessarily finished loading.   

Since your app-component html really looks more like a full page, including html head and body, maybe you should separate out the chart drawing parts into a chart-component.   

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Andrea Buzzi

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Sep 30, 2020, 1:06:05 PM9/30/20
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Hello Daniel,

I tried to move load from ngOninit() to ngAfterViewInit() but still getting same error, "google is not defined"

ngOnInit() {
}

ngAfterViewInit() {
google.charts.load('current', {'packages':['corechart']});
google.charts.setOnLoadCallback(this.drawChart);
}

I found a document ( https://anthonygiretti.com/2017/10/12/using-google-charts-in-angular-4-project-part-1/ ) that suggest to create first a class for a generic GoogleChartsBaseService then instantiate a PieChartConfig model where data can be passed along the different components.
While I'm sure that is the best way to approach this.... its logic is a bit too deep for me (for the time beeing at least)... so I'm really looking for a simple working snippet that I can load then adapt to my project....

Should you have any available.... :)

Thx,
Andrea

Daniel LaLiberte

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Sep 30, 2020, 1:34:48 PM9/30/20
to Google Visualization API
That article you reference appears to be doing the kind of things I imagine are necessary to load the loader and then call google.charts.load.  At the end of the second part is a link to the source, which may help you put together all the necessary parts.

To view this discussion on the web visit https://groups.google.com/d/msgid/google-visualization-api/83c32bac-f46c-4267-99f7-c2666325d1can%40googlegroups.com.

Andrea Buzzi

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Sep 30, 2020, 4:08:07 PM9/30/20
to Google Visualization API
Hello Daniel,

k, I followed:

 npm install

then because of "ERROR in DataTableModule is not an NgModule" I followed following tip:

 Just replace in app.module.ts:
 import { DataTableModule } from 'angular-4-data-table';
 with
 import { DataTableModule } from 'angular-4-data-table/src/index';

and now the Google Charts demo is working so I can analyze it.

Thank you so much for the appreciated time you took on providing guidance.

THx,
Andrea

Andrea Buzzi

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Oct 3, 2020, 8:45:10 AM10/3/20
to Google Visualization API
Hello,

finally I understood the issue I was facing...  I erroneously forgot that in angular application there is still a index.html (my bad).
So to have a example google graph (using old way) in a simple way just follow these instructions:

ng new test-ui

in 'src/index.html' add before </head>:
 <script type="text/javascript" src="https://www.gstatic.com/charts/loader.js"></script>

replace content of 'src/app/app.component.html' with:
  <div id="donutchart" style="width: 900px; height: 500px; border:solid 1px black;"></div>

replace 'src/app/app.component.ts' with:

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

declare var google: any;

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  title = 'test-ui';

  drawChart=function() {
  var data = google.visualization.arrayToDataTable([['Task', 'Hours per Day'], ['Work', 11], ['Eat', 2], ['Commute', 2], ['Watch TV', 2], ['Sleep', 7] ]);
  var options = { title: 'My Daily Activities', pieHole: 0.4 };
  var chart = new   google.visualization.PieChart(document.getElementById('donutchart'));
  chart.draw(data, options);
}

ngOnInit() {
  google.charts.load('current', {'packages':['corechart']});
  google.charts.setOnLoadCallback(this.drawChart);
}

}

Do "ng serve" and enjoy the graph displayed.

Thank you,
A.

Andrea Buzzi

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Oct 3, 2020, 9:30:51 AM10/3/20
to Google Visualization API
Hello,

one further note... if setOnLoadCallback call just drawChart then class variable (this.content) are not accessible:

drawChart() {
var srcdata = this.content["data"];   <= this element is not accessible
var data = google.visualization.arrayToDataTable(srcdata);   <= this is working fine
[...]
}

ngOnInit() {
google.charts.load('current', {'packages':['corechart']});
google.charts.setOnLoadCallback(this.drawChart);
}

if instead in setOnLoadCallback we call drawChart() then the google.visualization is not accessible:

drawChart() {
var srcdata = this.content["data"];   <= this element is accessible
var data = google.visualization.arrayToDataTable(srcdata);   <= this now fails
[...]
}

ngOnInit() {
google.charts.load('current', {'packages':['corechart']});
google.charts.setOnLoadCallback(this.drawChart);
}

I workaround that using:

ngOnInit() {
   google.charts.load('current', {'packages':['corechart']});
   setTimeout(() => {
     this.drawChart();
   }, 500);
}

The setTimeout allows too call drawChart() with access to the class variable (this.content) and also give enough time to fully load the google.visualization command.

Hope it helps.

Thx,
A.
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