Add a vertical line to line chart and only color to that line

[randohinn]

Say I have a graph like this

How can I add a line to any position vertically on the X axis and color the area under the main graph up to this line, such as this picture?

[kurkle]

I guess there are multiple ways, but I'd add a 2nd dataset, add 2 points to it with 0 as y-value and correct x-values, and fill it against the main line (fill: 0)

Example: https://codepen.io/kurkle/pen/PoeLwao

[Udemology]

Kurkle's method probably one the easiest and best methods to consider.

If you do not want to have an additional dataset in that case this might be useful. Using the background color with a gradient with an instant transitions in Chart js: https://youtu.be/O5iryKrXc8g