Type for Color missing string[] for indexable options

[jcoryalvernaz]

Expected Behavior

The Color type should support indexable options.

Current Behavior

The Typescript compiler will return the following error when providing an array of strings for an indexable color property (e.g. pointBackgroundColor):

Type 'string[]' is not assignable to type 'Color'

Possible Solution

Update the Color type definition to include an option for string[], as was previously done with DefinitleyTyped

[etimberg]

I'm not sure the definitely typed versions are correct. According to their types, the following is valid but it is won't be parsed correctly by https://github.com/kurkle/color.

const dataset = {
  pointBackgroundColor: [
    ['red', 'green'],
    ['blue', 'yellow']
  ]
}

Are you able to provide a full example showing how this format is used? I tested in using the latest dev code and the colours were not correctly applied

[jcoryalvernaz]

@etimberg I'm not sure that is correct. The DefinitelyTyped version allowed for an array of strings like so:

const dataset = {
  pointBackgroundColor: ['red', 'green'],
}

Which according to the Chart.js docs is an indexable option. This worked fine in v2 using the DefinitelyTyped type definitions. Now fails in v3 using the built-in type definitions.

[etimberg]

That is supported in v3 as well using. The definitely typed versions say that ChartColor[] is also allowed hence the nested arrays of strings being accepted in those definitions.

I just tested locally in our TS tests (using ts 4.3.5) and there were no errors. What TS version are you using?

const chart = new Chart('id', {
  type: 'line',
  data: {
    labels: [],
    datasets: [{
      data: [],
      pointBackgroundColor: ['red', 'green'],
    }]
  },
});

[jcoryalvernaz]

@etimberg We're also using 4.3.5. I'm not sure how TS isn't complaining since the type definition for Color doesn't look like it accepts an array type.

[etimberg]

Color itself doesn't, but the PointPrefixedOptions that contains pointBackgroundColor is transformed such that each property takes an array or a function as well. There have been a number of issues with TS >= 4.2.0 that were fixed in #9444. These were caused by changes inside of TS itself.

That PR hasn't been released yet, so v3.4.1 would only work as far as TS v4.1.x. This should be resolved once 3.5.0 releases

[kurkle]

If your chart type is 'radar', I sent #9426 to fix the types

[jcoryalvernaz]

@etimberg Ahh. I see. I'll keep my eye out for 3.5 then. Thanks for the quick reply and awesome work on this project!

[jcoryalvernaz]

@kurkle I was using the line chart type

[etimberg]

3.5.0 is released so this should be working now