Reset layout when nucleotide position is selected

[victorlin]

Description of proposed changes

Previously, this did not work because the dispatch to reset layout was conditional on having a CDS selected.

Related issue(s)

Closes #1774

Checklist

• Checks pass
• If making user-facing changes, add a message in CHANGELOG.md summarizing the changes in this PR
• (to be done by a Nextstrain team member) Create preview PRs on downstream repositories.

[jameshadfield]

If you've highlighted a nucleotide bar (in the entropy panel) and click "reset layout" the bar will no longer be highlighted because now action.selectedPositions = []; will be hit below.

[victorlin]

Simply dropping action.selectedPositions = [] doesn't work, I think because zoom bounds are tightly coupled with selected positions here:

auspice/src/components/entropy/entropyD3.js

Lines 131 to 145 in 1f40cd0

	if (this.selectedPositions?.length) {
	const posMin = Math.min(...this.selectedPositions);
	const posMax = Math.max(...this.selectedPositions);
	/* If we already have coordinates which are not the default, and the new
	positions are within the coordinates, then don't change zoom at all */
	if (
	this.zoomCoordinates &&
	(this.zoomCoordinates[0]!==domain[0] || this.zoomCoordinates[1]!==domain[1]) &&
	posMin>this.zoomCoordinates[0] && posMax<this.zoomCoordinates[1]
	) {
	return;
	}
	let desiredSurroundingSpace = Math.floor(domain[1] * 0.05); // 5%
	if (desiredSurroundingSpace>1000) desiredSurroundingSpace=1000; // up to a max of 1kb
	this.zoomCoordinates = [posMin - desiredSurroundingSpace, posMax + desiredSurroundingSpace];

[jameshadfield]

With this change (and the earlier change), the following just above this line becomes unnecessary and can be removed:

            if (viewingGenome) {
              this.state.chart.update({
                zoomMin: this.state.chart.zoomBounds[0],
                zoomMax: this.state.chart.zoomBounds[1],
              })
            }

This is because we end up running update({selectedPositions: []}) which runs

    if (selectedCds || selectedPositions !== undefined) {
      this._setZoomCoordinates(zoomMin, zoomMax, !!selectedCds);
    }

so we'll always reset the coordinates to show the entire nuc span.

[victorlin]

It's still used for when no CDS or position is selected, when the min/max sliders are adjusted. I think the update can happen elsewhere though. Started with 1f40cd0 but haven't gotten it fully working.