Small 10-point data breaks uplot

[danyalejandro]

https://jsbin.com/vuxizorupu/edit?html,js,console,output

Try zooming into an area with 6 samples or less, breaking in my Chrome.

Note that this error didn't happen in a previous version (not sure which one exactly)

[leeoniya]

i can't reproduce this :(

everything works okay for me when zooming down to 1 point, or even 0 points.

[danyalejandro]

Maybe some kind of cache error? It works for me now as well.

Try this one please:
https://jsbin.com/serocequha/edit?html,js,console,output
This one has a formatting option that I think is triggering the bug

[leeoniya]

This one has a formatting option

where? the code looks identical to the first jsbin.

[danyalejandro]

My fault, didn't save the right snapshot. This one should work:

https://jsbin.com/vuxizorupu/edit?html,js,console,output

[leeoniya]

ok, this was not a regression.

the minimal repro is this:

const data = [
  [
    1576713600.736,
    1576713601.727,
    1576713602.726,
    1576713603.727,
    1576713604.73,
    1576713605.73,
    1576713606.73,
    1576713607.73,
    1576713608.732,
    1576713609.731
  ],
  [
    3.38625,
    3.3866,
    3.38684,
    3.38697,
    3.38716,
    3.38741,
    3.38771,
    3.38744,
    3.38675,
    3.38649
  ]
];

const opts = {
  width: 400,
  height: 300,
  series: [{},{}],
};

let u = new uPlot(opts, data, document.body);

the cause of this was that uPlot found only 1 tick for the given data, plot width (400px) and the default combo of axis.space (50px) and axis.incrs (1,5,10,15,30...).

to reduce some redundancy in arguments, axis.values() relied on inferring the foundIncr from the difference between the first 2 ticks, which failed when only 1 tick was provided. the foundIncr is now passed explicitly to axis.values().

should be fixed.

[leeoniya]

the value formatting config you provided only goes down to 1s, so it will still error out if you try to zoom in too much since it lacks sub-second rules. but i assume that you'll avoid this by limiting zoom-in (#187) or something.

[leeoniya]

actually, rather than limiting zoom-in, you should just limit the max split resolution by restricting the bottom end of incrs so the axis cannot be split finer than the smallest available formatter:

axes: [
  {
    incrs: [
      1,
      5,
      10,
      15,
      30,
  //  ...
    ],
    values: [
      [3600 * 24 * 365,    "{YYYY}",            7,   "{YYYY}"                   ],
      [3600 * 24 * 28,     "{MMM}",             7,   "{MMM}\n{YYYY}"            ],
      [3600 * 24,          "{MMM}/{D}",         7,   "{MMM}/{D}\n{YYYY}"        ],
      [3600,               "{HH}:{mm}",         4,   "{HH}:{mm}\n{MMM}/{D}"     ],
      [60,                 "{HH}:{mm}",         4,   "{HH}:{mm}\n{MMM}/{D}"     ],
      [1,                  "{HH}:{mm}:{ss}",    4,   "{HH}:{mm}:{ss}\n{MMM}/{D}"]
    ]
  },
]