the reason yours doesnt look smooth and the one on the chart.js docs site does is that they use 1000 datapoints for their chart. so the transition from one point to next is not smooth but is perceived as smooth since the jump is verry small.

since you only have 4 datapoints the jumps are verry noticable and thus does not look smooth.

so if you want it to looks smooth you will need to add a lot more datapoints in between your current datapoints

Related Query

More Query from same tag