I’m programming a block in Drupal 8:

class B extends BlockBase implements BlockPluginInterface {   public function build() {     return []; // cannot figure out what to return here   } } 

I read that in D8 a block’s build function should return a render-array, like this:

return ['#markup' => 'Some HTML'];

Then in the Charts source code I found some examples here and there, especially in PHPDOC comments, so I built a render-array like this:

$  return = [   $  chart = [     '#type' => 'chart',     '#chart_type' => 'line',     '#chart_library' => 'c3',     'xaxis' => [                     '#type' => 'chart_xaxis',                     '#title' => 'XTitle',                     '#labels' => range(1, 10),                 ],     'yaxis' => [                     '#type' => 'chart_yaxis',                     '#title' => 'YTitle'                 ],     'series_1' => ['#type' => 'chart_data', '#title' => $  seriesTitle,                     '#data' => range(1, 10) ],     // more series here keyed series_2, series_3 etc   ] ]; 

Nothing is output (only block title). No JS errors in console. No error logs. Example chart in demo module works, C3 is installed.

What am I doing wrong?

Versions:

• Drupal: 8.4.2
• Charts: charts-8.x-3.0-alpha6