Fix bar chart with {x, y} data points

[nagix]

• Use the value scale to check the value when drawing bars
• Fix a document issue
• This fixes [BUG] Bars with {x, y} data points are not drawn on a time scale #4661.

[simonbrunel]

Then that's not anymore arrayUnique if it filters null values. Can we make that check elsewhere without iterating the whole array?

[nagix]

We can filter null out when the timestamps array is built, but not for the labels array because it is copied to datasets later.

Maybe we can do this way.

labels = arrayUnique(labels).sort(sorter);
if (labels[0] === null) {
    labels.shift();
}

timestamps = arrayUnique(timestamps).sort(sorter);
if (timestamps[0] === null) {
    timestamps.shift();
}

[nagix]

Ah, it doesn't work because a timestamp can be a negative value. We need to prepare both labels that doesn't contain null and rawLabels that can contain null.

[simonbrunel]

negative timestamp?

[etimberg]

negative timestamp would be before 1-1-1970

[nagix]

Moved the null check to the outside of arrayUnique.

[simonbrunel]

@etimberg do we support null in the data.labels array (what use case)? If not, I would consider that as an error and would avoid duplicating the labels timestamps array with rawLabels.

[etimberg]

I don't think null should be in data.labels

[simonbrunel]

@nagix are you sure we are actually checking the correct cases? I think we just want to skip null data but we should consider null timestamp an (user) error:

labels: ['2017', null, '2018']  // INVALID (what does that mean?)
data: [{x: null, y: 42}]        // INVALID (what does that mean?)
data: [42, null, 16]            // VALID (skip the second value mapped to the second label)

[nagix]

@simonbrunel Actually it is intended to check if timestamps are correctly parsed by parse function, rather to filter null timestamp. If that check is not required, I will remove that part.

[simonbrunel]

I think it's better to not gracefully handle invalid timestamps and have the user to provide correct inputs to the chart. Only explicitly null data must be ignored, everything else should be considered invalid user inputs generating invalid chart.

[nagix]

Agreed. I removed null timestamp checks.

[etimberg]

Can we merge this then?