How to add day numbers to d3 calendar heatmap?

@darrion.kuhn 

To add day numbers to a d3 calendar heatmap, you can follow these steps:

1. Create a grid of cells representing days in the calendar heatmap using d3's rect element.
2. Add text elements to each cell representing the day number.
3. Use a function to calculate the x and y positions of the text elements based on the cell's position in the grid.
4. Style the text elements with appropriate font size, color, and alignment.
5. Update the text content of each text element to display the corresponding day number.

Here is an example code snippet showing how you can add day numbers to a d3 calendar heatmap:

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// Create a grid of cells representing days in the calendar heatmap
const cell = svg.selectAll('rect')
  .data(data)
  .enter()
  .append('rect')
  .attr('x', function(d) { return d.day * cellSize; })
  .attr('y', function(d) { return d.week * cellSize; })
  .attr('width', cellSize)
  .attr('height', cellSize);

// Add text elements to each cell representing the day number
const text = svg.selectAll('text')
  .data(data)
  .enter()
  .append('text')
  .attr('x', function(d) { return d.day * cellSize + cellSize/2; })
  .attr('y', function(d) { return d.week * cellSize + cellSize/2; })
  .style('text-anchor', 'middle')
  .style('alignment-baseline', 'middle')
  .text(function(d) { return d.day; });

This code snippet assumes you have a dataset data containing the day numbers for each cell in the calendar heatmap. You can adjust the cellSize variable to control the size of each cell in the grid.

By following these steps and modifying the code to suit your specific needs, you can easily add day numbers to a d3 calendar heatmap.