Cannot read property 'length' of null #75
Description
Hello,
I just simply installed this (also installed canvas as npm install canvas and chart.js as npm install chart.js) and used the following code. and I got the below error.
var myChartOptions = {
plugins: {
afterDraw: function (chart, easing) {
var self = chart.config; /* Configuration object containing type, data, options */
var ctx = chart.chart.ctx; /* Canvas context used to draw with */
}
}
};
// xy is an array object as [{x:0,y:1},.....]
var chartJsOptions = {
type: 'scatter',
data: {datasets:[{data:xy}]},
options: myChartOptions
};
const ChartjsNode = require('chartjs-node');
var chartNode = new ChartjsNode(600, 600);
chartNode.drawChart(chartJsOptions)
.then(() => {
// chart is created
// get image as png buffer
return chartNode.getImageBuffer('image/png');
})
.then(buffer => {
if(Array.isArray(buffer)) return chartNode.getImageStream('image/png');
})
.then(streamResult => {
return chartNode.writeImageToFile('image/png', './testimage.png');
})
.then(() => {
// chart is now written to the file path
// ./testimage.png
});`
```
Unhandled rejection TypeError: Cannot read property 'length' of null
at Object.acquireContext (x:\\node_modules\chart.js\dist\Chart.js:6896:19)
at Chart.construct (x:\\node_modules\chart.js\dist\Chart.js:8415:26)
at new Chart (x:\\node_modules\chart.js\dist\Chart.js:8402:7)
at jsdom.envAsync.then.window (x:\\node_modules\chartjs-node\index.js:106:31)
at tryCatcher (x:\\node_modules\bluebird\js\release\util.js:16:23)
at Promise._settlePromiseFromHandler (x:\\node_modules\bluebird\js\release\promise.js:512:31)
at Promise._settlePromise (x:\\node_modules\bluebird\js\release\promise.js:569:18)
at Promise._settlePromise0 (x:\\node_modules\bluebird\js\release\promise.js:614:10)
at Promise._settlePromises (x:\\node_modules\bluebird\js\release\promise.js:694:18)
at Promise._fulfill (x:\\node_modules\bluebird\js\release\promise.js:638:18)
at Object.done (x:\\node_modules\bluebird\js\release\nodeback.js:42:21)
at process.nextTick (x:\\node_modules\jsdom\lib\jsdom.js:320:18)
at process._tickCallback (internal/process/next_tick.js:61:11)