Function intern_delete

external/.d3.js:459–466

({_intern, _key}, value)

}

function intern_delete({_intern, _key}, value) {
  const key = _key(value);
  if (_intern.has(key)) {
    value = _intern.get(key);
    _intern.delete(key);
  }
  return value;
}

function keyof(value) {
  return value !== null && typeof value === "object" ? value.valueOf() : value;