Clone y/y2-axis domain from the other y/y2-axis if no data is bound to one of them

[michkami]

Description

If there is no data bound to y2-axis and y2-axis is shown, it sets the domain of y2-axis to [0, 1].
The same happens if no data is bound to y-axis.
All columns bound to y-axis:

For setting the domain of y2-axis you have to bind atleast one data column to y2-axis.
'data3' bound to y2-axis:

For the case of showing the both y- and y2-axis and not binding data to one of them, it would be great if it would clone the domain of the opposite y-axis per default.

It would look like this:
All columns bound to y-axis:

'data3' bound to y2-axis:

It can be achieved by changing following code in domain.js:

97	if (yTargets.length === 0) { // use current domain if target of axisId is none
98		return $$[axisId].domain();
99	}

change to

97	if (yTargets.length === 0) { // use current domain if target of axisId is none
98		return axisId === "y2" ? $$.y.domain() : $$.getYDomain(targets, "y2", false);
99	}

Is there anything against implementing this in billboard?

Steps to check or reproduce

1. Open CategoryAxis Example
2. Use the code below.

Example code:

var chart = bb.generate({
  data: {
    columns: [
		['data1', -1000, -750, -500, -250, 0, 250, 500, 750, 1000],
		['data2', -250, 0, 250, 0, -250, 0, 250, 0, -250],
		['data3', 100, 75, 50, 25, 0, -25, -50, -75, -100]
    ],
	axes: {
		data1: 'y',
		data2: 'y',
		data3: 'y'
	}
  },
  axis: {
    x: {
      type: "category",
      categories: [
        "cat1",
        "cat2",
        "cat3",
        "cat4",
        "cat5",
        "cat6",
        "cat7",
        "cat8",
        "cat9"
      ]
    },
	y2: {
		show: true
	}
  },
  bindto: "#categoryAxis"
});

[netil]

Hi @michkami, thanks for the suggestion and it sounds reasonable.
Is changing default behavior which will affect those are using as is, but there's no meaning showing y2 Axis without correlating with the data bound.

Can you send PR for this? And don't forget adding changes to API doc.

[netil]

🎉 This issue has been resolved in version 1.12.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀