@uwdata/mosaic-plot/src/interactors/util/patchScreenCTM.js

A Mosaic-powered plotting framework based on Observable Plot.

/**
 * Patch the getScreenCTM method to memoize the last non-null
 * result seen. This will let the method continue to function
 * even after the node is removed from the DOM.
 */
export function patchScreenCTM() {
  /** @type {SVGGraphicsElement} */
  // @ts-ignore
  const node = this;
  const getScreenCTM = node.getScreenCTM;
  let memo;
  node.getScreenCTM = () => {
    return node.isConnected ? (memo = getScreenCTM.call(node)) : memo;
  };
}