CODEWITHSUNDEEP
javascriptarrayshighchartsgetjsonundefined-behavior
jamesp777
jamesp777

Reputation: 51

Highcharts Remote Data - JSON Object Undefined

I'm trying to render a Highcharts column chart from MySQL data -> json_encode() -> getJSON(). 95% of the time there are 6 rows of data to process, so this can be easily looped through manually and the chart renders fine. The problem is when there are occasionally fewer rows in the results array - I am of course seeing TypeError: Cannot read property 'name' of undefined in these cases. My working code:

$.getJSON(url, function(json)) {
    if(typeof json === 'object' && json.length > 0) {
        var nameData = [json[0]['name'],json[1]['name'],json[2]['name'],json[3]['name'],json[4]['name'],json[5]['name']];

        var matchedData = [json[0]['data']['Matched'],json[1]['data']['Matched'],json[2]['data']['Matched'],json[3]['data']['Matched'],json[4]['data']['Matched'],json[5]['data']['Matched']];

        var bookedData = [json[0]['data']['Booked'],json[1]['data']['Booked'],json[2]['data']['Booked'],json[3]['data']['Booked'],json[4]['data']['Booked'],json[5]['data']['Booked']];
    }
    var options = {
        chart: {
            renderTo: 'div',
            type: 'column'
        },
        title: {
            text: 'Chart Title',
            x: -20
        },
        xAxis: {
            type: 'category',
            categories: nameData,
            crosshair: true
        },
        series: [{
            name: 'Matched',
            data: matchedData
        }, {
            name: 'Booked',
            data: bookedData
        }]
    }
    chart = new Highcharts.Chart(options);
}

This renders the chart correctly. However when there are fewer than the usual 6 items in the array, the TypeError stops things. I attempted this to count the array items prior to sending to Highcharts:

var nameData = [];
var matchedData = [];
var bookedData = [];
if (typeof json === 'object' && json.length > 0) {
    for (var a = 0; a < json.length; a++) {
        nameData += [json[a]['name']+","];
        matchedData += [json[a]['data']['Matched']+","];
        bookedData += [json[a]['data']['Booked']+","];
    }
}

This alerts() out the same results as the manually-created array, but nothing renders on the chart. What needs to change?

Upvotes: 1

Views: 77

Answers (1)

Christopher Bradshaw
Christopher Bradshaw

Reputation: 2783

Try mapping over your data. You can set everything really easily using the map function. It's a lot cleaner and simpler as well. You can find a reference for map here.

$.getJSON(url, function(json)) {
    if(typeof json === 'object' && json.length > 0) {
        var nameData = json.map(obj => obj['name']);

        var matchedData = json.map(obj => obj['data']['Matched']);

        var bookedData = json.map(obj => obj['data']['Booked']);
    }
    var options = {
        chart: {
            renderTo: 'div',
            type: 'column'
        },
        title: {
            text: 'Chart Title',
            x: -20
        },
        xAxis: {
            type: 'category',
            categories: nameData,
            crosshair: true
        },
        series: [{
            name: 'Matched',
            data: matchedData
        }, {
            name: 'Booked',
            data: bookedData
        }]
    }
    chart = new Highcharts.Chart(options);
}

Upvotes: 1

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