charts.js - json output to graph

Question

I want to dispay in a bar graph the days and the quantity. I have following json output.(data.php) for each day the quantity.

[{"day":"2017-11-15","quantity":"72"},{"day":"2017-11-16","quantity":"157"},{"day":"2017-11-17","quantity":"130"},{"day":"2017-11-18","quantity":"91"},{"day":"2017-11-19","quantity":"96"}]

output.html

 <!DOCTYPE html>
 <html>
 <head>
 <title>ChartJS - BarGraph</title>
     <style type="text/css">
        #chart-container {
            width: 640px;
            height: auto;
        }
    </style>
</head>
<body>
    <div id="chart-container">
        <canvas id="mycanvas"></canvas>
    </div>

    <!-- javascript -->
    <script type="text/javascript" src="js/jquery.min.js"></script>
    <script type="text/javascript" src="js/Chart.min.js"></script>
    <script type="text/javascript" src="js/app.js"></script>
</body>

and thats the app.js

$(document).ready(function(){
$.ajax({
    url: "data.php",
    method: "GET",
    success: function(data) {
        console.log(data);
        var day = [];
        var quantity = [];

        for(var i in data) {
            day.push(data[i].day);
            quantity.push(data[i].quantity);
        }

        var chartdata = {
            labels: day,
            datasets : [
                {
                    label: 'DAYS',
                    backgroundColor: 'rgba(200, 200, 200, 0.75)',
                    borderColor: 'rgba(200, 200, 200, 0.75)',
                    hoverBackgroundColor: 'rgba(200, 200, 200, 1)',
                    hoverBorderColor: 'rgba(200, 200, 200, 1)',
                    data: quantity
                }
            ]
        };

        var ctx = $("#mycanvas");

        var barGraph = new Chart(ctx, {
            type: 'bar',
            data: chartdata
        });
    },
    error: function(data) {
        console.log(data);
    }
});
});

but it's always empty. but why? Any idea? Also instead of the day theres only undefined on the bottom line.

Alex Baban · Accepted Answer · 2017-11-30 00:40:34Z

1

Here is the main idea

data.forEach(function(packet) {

  labelsData.push(packet.day);
  datasetData.push(parseFloat(packet.quantity));

});

for example

var dataJSON = [{
  "day": "2017-11-15",
  "quantity": "72"
}, {
  "day": "2017-11-16",
  "quantity": "157"
}, {
  "day": "2017-11-17",
  "quantity": "130"
}, {
  "day": "2017-11-18",
  "quantity": "91"
}, {
  "day": "2017-11-19",
  "quantity": "96"
}];

var labelsData = [];
var datasetData = [];

dataJSON.forEach(function(packet) {

  labelsData.push(packet.day);
  datasetData.push(parseFloat(packet.quantity));

});

var chartdata = {
  type: 'bar',
  data: {
    labels: labelsData,
    datasets: [{
      label: 'DAYS',
      data: datasetData
    }]
  }
}

Working JSFiddle

https://jsfiddle.net/4v3nt7sL/1/

edited Nov 30, 2017 at 0:40

answered Nov 30, 2017 at 0:19

Alex Baban

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Comments

Patrick Duke Schauer · Accepted Answer · 2017-11-30 18:33:48Z

no plan why it's empty for me..

my database output is correct it think!

data.php

[{"day":"15","quantity":"72"},{"day":"16","quantity":"157"},{"day":"17","quantity":"130"},{"day":"18","quantity":"91"},{"day":"19","quantity":"96"},{"day":"20","quantity":"129"},{"day":"21","quantity":"140"},{"day":"22","quantity":"141"}]

index.html

<!DOCTYPE html>
<html>
<head>
    <title>a simple chart</title>
    <style type="text/css">
        #chart-container {
            width: 640px;
            height: auto;
        }
    </style>
</head>
<body>
    <div id="chart-container">
        <canvas id="mycanvas"></canvas>
    </div>

    <!-- javascript -->
    <script type="text/javascript" src="js/jquery.min.js"></script>
    <script type="text/javascript" src="js/Chart.min.js"></script>
    <script type="text/javascript" src="js/app.js"></script>
</body>
</html>

app.js

$.ajax({
type: 'POST',
url: 'data.php',
success: function (data) {
    lineChartData = JSON.parse(data); //parse the data into JSON

    var ctx = document.getElementById("mycanvas").getContext("2d");
    var myLineChart = new Chart(ctx, {
        type: 'line',
        data: lineChartData
    });
}
});

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