Chart.js 散点格式数据 plot

Question

Chart.js scatter chart only accepts data in a point format (x, y). Im a trying to fill the data points with infomration about medications from a file called meds.json More specifically, the x would be the month of last fill date of the medication and the y would be the dose.

How can I grab all this data from the meds.json file and insert it to the data to create the points for my scatter plot? If I try to grab all dates and store them in an array, and all the dose values in another array, how can I use that populate the point data using those arrays?

Here's how to make a scatter plot using Chart.js, I am trying to populate the x,y points under data 'data':

// charts.js
var scatterChart = new Chart(ctx, {
        type: 'scatter',
        data: {
            datasets: [{
                label: 'Scatter Dataset',
                data: [{
                    // x = month, y = dose
                    // fill these in for all meds in the json file
                    x: -10,
                    y: 0
                }, {
                    x: 0,
                    y: 10
                }, {
                    x: 10,
                    y: 5
                }]
            }]
        },
        options: {
            scales: {
                xAxes: [{
                    type: 'linear',
                    position: 'top'
                }]
            }
        }
    });
}

meds.json

[
  {
    "name": "Simvastatin",
    "dose": 10,
    "dose unit": "mg",
    "freq": "qd",
    "route": "PO",
    "last fill date": "2/15/2020",
    "coverage": "100%",
    "anticipated remaining fills": 2
  },
  {
    "name": "Lisinopril",
    "dose": 5,
    "dose unit": "mg",
    "freq": "qd",
    "route": "PO",
    "last fill date": "2/15/2020",
    "coverage": "100%",
    "anticipated remaining fills": 2
  }  

    ...... The list goes on

]

Answer 1

You should actually use a line chart for this which would be much more appropriate and exactly show the trend & relationship between month and the dosage.

But since you asked for scatter chart...you can do it like this:

 const data = [{ "name": "Simvastatin", "dose": 10, "dose unit": "mg", "freq": "qd", "route": "PO", "last fill date": "2/15/2020", "coverage": "100%", "anticipated remaining fills": 2 }, { "name": "Lisinopril", "dose": 5, "dose unit": "mg", "freq": "qd", "route": "PO", "last fill date": "2/15/2020", "coverage": "100%", "anticipated remaining fills": 2 } ] const transformedData = data.map(obj=>{ return { x:new Date(obj["last fill date"]).getMonth() + 1, y:obj.dose, } }) console.log(transformedData)

and then use as

var scatterChart = new Chart(ctx, {
        type: 'scatter',
        data: {
            datasets: [{
                label: 'Scatter Dataset',
                data: transformedData
            }]
        },
        options: {
            scales: {
                xAxes: [{
                    type: 'linear',
                    position: 'top'
                }]
            }
        }
    });
}

Hope this helps !