Cannot plot a chart with a single repeating value (horizontal line)

[pghalliday]

When I try to plot a chart with an array of values such as [100, 100, 100], eg.

var asciichart = require('asciichart');
asciichart.plot([100, 100, 100], {
  height: 10,
});

I get the following error

/Users/pghalliday/projects/github/pghalliday/metriculator/node_modules/asciichart/asciichart.js:29
        let result = new Array (rows + 1) // empty space
                     ^

RangeError: Invalid array length
    at Object.exports.plot (/Users/pghalliday/projects/github/pghalliday/metriculator/node_modules/asciichart/asciichart.js:29:22)
    at Object.<anonymous> (/Users/pghalliday/projects/github/pghalliday/metriculator/test.js:2:12)
    at Module._compile (module.js:662:30)
    at Object.Module._extensions..js (module.js:673:10)
    at Module.load (module.js:575:32)
    at tryModuleLoad (module.js:515:12)
    at Function.Module._load (module.js:507:3)
    at Function.Module.runMain (module.js:703:10)
    at startup (bootstrap_node.js:193:16)
    at bootstrap_node.js:660:3

This seems to be due to the way the number of rows are calculated based on the range (which in this case I presume is calculated to zero). The same error occurs if I supply an empty array or an array with just 1 value. I think a possible fix would be to define a default range if one cannot be sensibly calculated. This should probably be added to the options in some way.

This impacts me as I'm starting with an empty chart and adding values over time. For now I have worked around it by ensuring that the range is non-zero before plotting. However this leads to an odd corner case where the last n entries for a chart that only plots n entries (due to screen width) are all equal (even if previous entries are not) then the chart cannot be updated.

[kroitor]

Thanks for reporting! Will fix asap!

[arkihillel]

I'm also getting a flat line with a NaN when the numbers are really small:

[0.4000000189989805,0.20000000949949026,0.3000000142492354,0.19999995129182935,0.3000000142492354,0.10000000474974513,0.3000000142492354,0.10000000474974513,0.10000000474974513]

Result calling a simple char.plot():

    NaN ┼──────── 

[sheerun]

Same issue..

[ourarash]

I have the same problem