The axis mark requires a range interval, but doesn’t check for it

[mbostock]

For example, if you say

Plot.plot({
  x: {
    domain: [0, 10],
    interval: {
      floor: (x) => Math.floor(x),
      offset: (x, offset = 1) => x + offset
    }
  }
})

you get

TypeError: interval.range is not a function

here

plot/src/marks/axis.js

Line 521 in 6b87468

data = interval.range(min, interval.offset(interval.floor(max))); // inclusive max

You can fix the problem like so

Plot.plot({
  x: {
    domain: [0, 10],
    interval: <Plot.RangeInterval>{
      floor: (x) => Math.floor(x),
      offset: (x, offset = 1) => x + offset,
      range: (x1, x2) => d3.range(x1, x2)
    }
  }
})

but you need the type declaration to avoid a lint error, since ScaleOptions["interval"] is also erroneously an Interval instead of a RangeInterval. Though, there are some cases like with ordinal scales where a plain Interval may be allowable?

We should decide whether a range interval is required for the ScaleOptions["interval"] option. If it’s not, then the axis mark should gracefully handle the interval not implementing interval.range. If it is, then the axis mark should throw a nicer “invalid interval” error message.