area.y1()

area.y1([y])

If y is specified, sets the y1 accessor to the specified function or number and returns this area generator. If y is not specified, returns the current y1 accessor, which defaults to:

function y(d) {
  return d[1];
}

A null accessor is also allowed, indicating that the previously-computed y0 value should be reused for the y1 value. When an area is generated, the y1 accessor will be invoked for each defined element in the input data array, being passed the element d, the index i, and the array data as three arguments. See area.x0 for more information.