Looks like tip.offset() receive array but expect swapped x vs. y values

In line https://github.com/Caged/d3-tip/blob/master/index.js#L139 it says // v - Array of [x, y] offset

I tried my code changes, and assumed I was changing x value, in fact I was changing y value. I'm using v0.6.8 version for d3 v3.5.7

And my code to set the offset:

 var tip = d3Tip()
        .attr('class', 'd3-tip')
        .offset([-10, 0])

So this code gives my -10 up by y axis, and x axis still remain 0, so that my tip rendered for 10px above.

Is this correct behavior? Is it wrong comment? Have I done smth wrong?

PS. I see, that even in live demo/example, there is also -10 applied: http://bl.ocks.org/Caged/6476579

var tip = d3.tip()
  .attr('class', 'd3-tip')
  .offset([-10, 0])
  .html(function(d) {
    return "<strong>Frequency:</strong> <span style='color:red'>" + d.frequency + "</span>";
  })

UPD: Looks like all is ok, because in fact if y = 10, then it goes down (for SVG, rect), not as original coordinate systsem.

caged / d3-tip

Looks like tip.offset() receive array but expect swapped x vs. y values #217