Append one transform chain to another (concat chains)

[sompylasar]

If you have two existing transform objects, it would be great if you could append one to another after constructing. This is required for better transform reuse.

Example (zoom with a center point):

import d3Transform from 'd3-transform';

const zoomTransform = d3Transform().scale(1.5);

// The 'x' and 'y' are calculated from the bounding box.
const originForwardTransform= d3Transform().translate([ x, y ]);
const originBackwardTransform= d3Transform().translate([ -x, -y ]);

// Notice the order.
const zoomCenteredTransform = d3Transform()
  .concat(originForwardTransform)
  .concat(zoomTransform)
  .concat(originBackwardTransform);

[seliopou]

Should be easy to implement. seq may be a better name than concat, as it connotes more of an operation on actions rather than slapping together data.