How to use Fetch API to Automatically Update Data with JSON in Chart JS

How to use Fetch API to Automatically Update Data with JSON in Chart JS

In this video we will explore how to use fetch API to automatically update data with JSON in Chart js. Using the fetch API in Chart js means you need to work from your local server else it will not work.

What we will do is extract the values and once we extra the values we will feed them to the chart gradually one at the time. Secondly we need to remove the old feed once we have more than 12 data points. We will use fetch API with async connection and getting it all from a JSON file we have on our server.

Let's explore this right now!

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[ChartJS-tutorials]

Need the sample JSON file? Copy and past this info below and save as financials.json

{
"year": "2021",
"financialreport": [
{
"company": "ChartJS",
"companyname": "ChartJS Corp",
"companystock": "CHRT",
"financials":
[
{
"date": "January",
"revenue": 90,
"expenses": 30,
"profits": 60,
"target": "Target 1"
},
{
"date": "February",
"revenue": 120,
"expenses": 30,
"profits": 90,
"target": "Target 2"
},
{
"date": "March",
"revenue": 150,
"expenses": 30,
"profits": 120,
"target": "Target 3"
},
{
"date": "April",
"revenue": 180,
"expenses": 30,
"profits": 150,
"target": "Target 4"
},
{
"date": "May",
"revenue": 210,
"expenses": 30,
"profits": 180,
"target": "Target 5"
},
{
"date": "June",
"revenue": 240,
"expenses": 30,
"profits": 210,
"target": "Target 6"
},
{
"date": "July",
"revenue": 270,
"expenses": 30,
"profits": 240,
"target": "Target 7"
},
{
"date": "August",
"revenue": 8,
"expenses": 8,
"profits": 8,
"target": "Target 8"
},
{
"date": "September",
"revenue": 9,
"expenses": 9,
"profits": 9,
"target": "Target 9"
},
{
"date": "October",
"revenue": 10,
"expenses": 10,
"profits": 10,
"target": "Target 10"
},
{
"date": "November",
"revenue": 11,
"expenses": 11,
"profits": 11,
"target": "Target 11"
},
{
"date": "December",
"revenue": 12,
"expenses": 12,
"profits": 12,
"target": "Target 12"
},
{
"date": "January 2022",
"revenue": 1,
"expenses": 1,
"profits": 1,
"target": "Target 1"
},
{
"date": "February 2022",
"revenue": 2,
"expenses": 2,
"profits": 2,
"target": "Target 2"
},
{
"date": "March 2022",
"revenue": 3,
"expenses": 3,
"profits": 3,
"target": "Target 3"
},
{
"date": "April 2022",
"revenue": 4,
"expenses": 4,
"profits": 4,
"target": "Target 4"
},
{
"date": "May 2022",
"revenue": 5,
"expenses": 5,
"profits": 5,
"target": "Target 5"
},
{
"date": "June 2022",
"revenue": 6,
"expenses": 6,
"profits": 6,
"target": "Target 6"
},
{
"date": "July 2022",
"revenue": 7,
"expenses": 7,
"profits": 7,
"target": "Target 7"
},
{
"date": "August 2022",
"revenue": 8,
"expenses": 8,
"profits": 8,
"target": "Target 8"
},
{
"date": "September 2022",
"revenue": 9,
"expenses": 9,
"profits": 9,
"target": "Target 9"
},
{
"date": "October 2022",
"revenue": 10,
"expenses": 10,
"profits": 10,
"target": "Target 10"
},
{
"date": "November 2022",
"revenue": 11,
"expenses": 11,
"profits": 11,
"target": "Target 11"
},
{
"date": "December 2022",
"revenue": 12,
"expenses": 12,
"profits": 12,
"target": "Target 12"
}
]
},
{
"company": "ChartFlix",
"companyname": "ChartFlix Inc.",
"companystock": "CX",
"financials":
[
{
"date": "January",
"revenue": 270,
"expenses": 30,
"profits": 240,
"target": "Target 21"
},
{
"date": "February",
"revenue": 180,
"expenses": 30,
"profits": 150,
"target": "Target 22"
},
{
"date": "March",
"revenue": 150,
"expenses": 30,
"profits": 120,
"target": "Target 23"
},
{
"date": "April",
"revenue": 210,
"expenses": 30,
"profits": 180,
"target": "Target 24"
},
{
"date": "May",
"revenue": 120,
"expenses": 30,
"profits": 90,
"target": "Target 25"
},
{
"date": "June",
"revenue": 180,
"expenses": 30,
"profits": 150,
"target": "Target 26"
},
{
"date": "July",
"revenue": 210,
"expenses": 30,
"profits": 180,
"target": "Target 27"
}
]
},
{
"company": "Chart Start Up",
"companyname": "Chart Start Up",
"companystock": "START",
"financials":
[
{
"date": "January",
"revenue": 3,
"expenses": 1.5,
"profits": 2.5,
"target": "Target 31"
},
{
"date": "February",
"revenue": 6,
"expenses": 3,
"profits": 3,
"target": "Target 32"
},
{
"date": "March",
"revenue": 9,
"expenses": 6,
"profits": 3,
"target": "Target 33"
},
{
"date": "April",
"revenue": 18,
"expenses": 9,
"profits": 9,
"target": "Target 34"
},
{
"date": "May",
"revenue": 12,
"expenses": 3,
"profits": 9,
"target": "Target 35"
},
{
"date": "June",
"revenue": 24,
"expenses": 18,
"profits": 6,
"target": "Target 36"
},
{
"date": "July",
"revenue": 18,
"expenses": 18,
"profits": 0,
"target": "Target 37"
}
]
}
]
}

[ciaranrobinson]

this was so helpful!! These videos have been amazing, great work

[hung-linwu]

great, amazing tutorial, it’s useful to me, thanks a lot
I have two question(Situation)
below case need using API
1) How to load 12 items at the beginning and then move forward(shift)
2) one chart, the x-axis item already fixed display, and at this time some value already loading, and next time new value how to put in x-scale-axis

[jenshartmann]

Is it possible to automatically update the data without having the user to push any button? For example, based on preset period of time like every 24hrs OR whenever the page is loaded/refreshed. Or is it necessary to let the user manually pull fresh data using the button? Thank you!