Error with interpolate [duplicate]

Answer 1

Instead of:

const area = d3.area()
    .interpolate('cardinal')
    .x(d => xScale(parseTime(d.data.date)))
    .y0(d => yScale(d[0] || 0))
    .y1(d => yScale(d[1] || 0));

It has to be:

const area = d3.area()
    .curve(d3.curveCardinal)
    .x(d => xScale(parseTime(d.data.date)))
    .y0(d => yScale(d[0] || 0))
    .y1(d => yScale(d[1] || 0));

Here is the API regarding the curves: https://github.com/d3/d3-shape/blob/master/README.md#curves