Issues using highcharts node export server from ClojureScript - “0x03 error when performing chart generation”

Question

I have a clojurescript app on Node.js, and am attempting to use the highcharts export server as a Node.js module in order to generate charts for the purpose of PDF generation.

I have followed the example as seen under "Using as a Node.js Module" here: https://github.com/highcharts/node-export-server . This example uses the following javascript object as input data for the chart:

var exportSettings = {
type: 'png',
options: {
        title: {
            text: 'My Chart'
        },
        xAxis: {
            categories: ["Jan", "Feb", "Mar", "Apr", "Mar", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
        },
        series: [
            {
                type: 'line',
                data: [1, 3, 2, 4]
            },
            {
                type: 'line',
                data: [5, 3, 4, 2]
            }
        ]
    }
};

Replicating this example in clojurescript, defining the export settings as a clojurescript map and converting it back to a javascript object:

(def test-chart (clj->js {:type    "png"
                      :options {:title  {:text "My Chart"}
                                :xAxis  {:categories ["Jan", "Feb", "Mar", "Apr", "Mar", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]}
                                :series [{:type "line"
                                          :data [1 3 2 4]}
                                         {:type "line"
                                          :data [5 3 4 2]}]}}))

Logging the test-chart object to console confirms it's identical to the javascript object used in the example:

{ type: 'png',  
  options: { title: { text: 'My Chart' },     
             xAxis: { categories: [Array] },     
             series: [{ type: 'line', data: [ 1, 3, 2, 4 ] },
                      { type: 'line', data: [ 5, 3, 4, 2 ] }] 
    } 
}

Further calling the required Highcharts functions to set up a phantom.js worker pool and generate the chart as seen in the example:

(doto Highcharts
(.initPool)
(.export test-chart (fn [err res]
                      (when err (println "****" err))))
(.killPool))

When calling export with the converted clojure map as input data, the error "0x03 error when performing chart generation: please check your input data" is seen.

The documentation example does work in regular Node.JS, but when calling export from clojurescript using input data converted from a clojure map, the export fails with this input data error. As the converted object looks correct from console, and everything else should be identical just done through javascript interop, I am not sure what the issue could be here.

Is there something that would cause the exporter to be unable to parse the input data object if converted from a clojure map? Or could the issue be something else, and checking input data is a misleading error message?

Answer 1

Your ClojureScript code is not equivalent to the example code in the readme. In the example, killPool is called in the callback function passed into export . In your version, you call killPool immediately after calling export so chart generation likely does not have time to finish. I suspect this is causing the error.

The updated ClojureScript would look like this:

(doto Highcharts
  (.initPool)
  (.export test-chart (fn [err res]
                        (when err (println "****" err))
                        (.killPool Highcharts))))