score:0

I understand you want to update view with new fresh json data every xx ms in summary you need to :

  • have a service which exposes a shared observable, say data$;
  • the service has the method to fetch the remote data and update the shared observable above, say getRemoteData()
  • that service Observable.interval() which calls the method to fetch the remote data
  • have your component that displays the data
  • have the component subscribe to the data observable from the service.

the next sample code illustrates how to implement it 

import {takeWhile, first} from 'rxjs/operators';
import { Component, OnInit } from '@angular/core';
import { interval } from "rxjs";
import { PositionsModel } from "./positionsmodel";
import { MouvementService } from './mouvement.service';

@Component({
  selector: 'app-mouvementview',
  template: '<div *ngIf="data"> your chart </div>',
})

export class MouvementviewComponent implements OnInit {
  public data: PositionsModel;
  private display: boolean; // whether to display info in the component
                            // use *ngIf="display" in your html to take
                            // advantage of this
  private alive: boolean; // used to unsubscribe from the IntervalObservable
                          // when OnDestroy is called.
  results : string;
  // Inject mouvementService
  constructor(private mouvementService: MouvementService) {
    this.display = false;

    }

ngOnInit() {
   this.mouvementService.getPositions().pipe(
      first()) // only gets fired once
      .subscribe((data) => {
        this.data = data;
        this.display = true;
        this.alive = true;
});

// get our data every subsequent 200 mseconds
interval(200).pipe(
      takeWhile(() => this.alive)) // only fires when component is alive
      .subscribe(() => {
        this.mouvementService.getPositions()
          .subscribe(data => {
        console.log(data);
        this.data = data;
          });
      });

}

ngOnDestroy(){
    this.alive = false; // switches your IntervalObservable off
  }
}

score:0

You can use Chart.js's addData() function with a setTimeout method for this.

<!DOCTYPE html>
<html>
    <head>
         <title>Add data</title>
         <script src = "https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.7.3/Chart.js"></script>
    </head>
    <body>      
        <div class = "container">
            <canvas id="myChart"></canvas>            
        </div>
        <script src = "script.js"></script>
    </body>
</html>

script.js

let ctx = document.getElementById("myChart").getContext('2d');
        let myChart = new Chart(ctx, {
            type: 'line',
            data: {
                labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"],
                datasets: [{
                    label: '# of Votes',
                    data: [7, 9, 3, 5, 2, 3],
                    backgroundColor: [
                        'rgba(255, 99, 132, 0.2)',
                        '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)'
                    ],
                    borderColor: [
                        'rgba(255,99,132,1)',
                        'rgba(54, 162, 235, 1)',
                        'rgba(255, 206, 86, 1)',
                        'rgba(75, 192, 192, 1)',
                        'rgba(153, 102, 255, 1)',
                        'rgba(255, 159, 64, 1)'
                    ],
                    borderWidth: 1
                }]
            },
            options: {
                scales: {
                    yAxes: [{
                        ticks: {
                            beginAtZero:true
                        }
                    }]
                }
            }
        });

        setTimeout(function() {
            addData(myChart, "White", 7);
        },3000);

        function addData(chart, label, data) {
            console.log(console.log(chart.data.datasets[0].data));
            chart.data.labels.push(label);
            chart.data.datasets[0].data.push(data);
            chart.update();
        }

Hope this could be helpful. You can change setTimeout to setInterval if you prefer adding data to the chart in intervals (such as every 2 secs).

score:2 

test_data = {
    '1222': {
        joy: 66.5057373046875,
        fear: 1.0003513832343742,
        anger: 2.000018799044483,
        disgust: 3.004251452162862,
        sadness: 4.0001135088386945,
        contempt: 5.001299204188399,
        surprise: 6.203749045729637
    },
    '2238': {
        joy: 97.06363677978516,
        fear: 17.500137131541123,
        anger: 27.00000593749519,
        disgust: 6.001324078417383,
        sadness: 21.000043172625737,
        contempt: 21.00033742573578,
        surprise: 32.62530106306076
    },
    '3722': {
        joy: 66.5057373046875,
        fear: 60.000351383234374,
        anger: 70.00001879904448,
        disgust: 10.004251452162862,
        sadness: 92.0001135088387,
        contempt: 40.0012992041884,
        surprise: 50.20374904572964
    },
    '4838': {
        joy: 97.06363677978516,
        fear: 15.000137131541123,
        anger: 64.50000593749519,
        disgust: 24.501324078417383,
        sadness: 31.500043172625737,
        contempt: 18.50033742573578,
        surprise: 6.2048268765211105
    },
    '5722': {
        joy: 66.5057373046875,
        fear: 54.000351383234374,
        anger: 72.00001879904448,
        disgust: 0.004251452162861824,
        sadness: 80.0001135088387,
        contempt: 20.0012992041884,
        surprise: 20.203749045729637
    },
    '6838': {
        joy: 95.37223815917969,
        fear: 41.000168004859006,
        anger: 62.00000752212509,
        disgust: 33.001674098544754,
        sadness: 3.000052563053032,
        contempt: 44.00044780407916,
        surprise: 4.204549819231033
    },
    '7839': {
        joy: 98.75503540039062,
        fear: 1.0001062582232407,
        anger: 1.0000043528652895,
        disgust: 1.0009740582900122,
        sadness: 2.000033782198443,
        contempt: 2.0002270473924,
        surprise: 1.2051039338111877
    }
};

var arr = Object.entries(test_data)


var options = {
    type: 'line',
    data: {
        labels: ["joy", "fear", "anger", "disgust", "sadness", "contempt", "surprise"],
        datasets: []
    },
    options: {
        scales: {
            yAxes: [{
                ticks: {
                    reverse: false
                }
            }]
        }
    }
}




var ctx = document.getElementById('chartJSContainer').getContext('2d');
var myC = new Chart(ctx, options);


arr.forEach((v) => {
    setTimeout(() => {


        myC.data.datasets.push({
            data: [v[1].joy, v[1].fear, v[1].anger, v[1].disgust, v[1].sadness, v[1].contempt, v[1].surprise],
            label: "#" + v[0] + "Milisec"
        });
        myC.update()
    }, parseInt(v[0]))
})
canvas { background-color : #eee;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.4.0/Chart.min.js"></script>

<body>
    <canvas id="chartJSContainer" width="600" height="400"></canvas>
</body>


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