Chartjs-Ng2-charts How to get the result of multiple push?

You are binding data to the wrong property of canvas element/object. When you have array of multiple datasets, you must bind it to the datasets property, instead of data.

Also, you should bind the datasets property of your class (not data_in) to [datasets]
(here setTimeout is not doing what you think it is)

...
<canvas baseChart width="400" height="200"
        [datasets]="datasets"
        [labels]="labels"
        [options]="lineChartOptions"
        [colors]="lineChartColors"
        [legend]="lineChartLegend"
        [chartType]="lineChartType"
        (chartHover)="chartHovered($event)"
        (chartClick)="chartClicked($event)">
 </canvas>
...

see- working example
^{(uses minimal code required)}