Function getOrCreateStack

src/core/core.datasetController.js:136–139

(stacks, stackKey, indexValue)

}

function getOrCreateStack(stacks, stackKey, indexValue) {
  const subStack = stacks[stackKey] || (stacks[stackKey] = {});
  return subStack[indexValue] || (subStack[indexValue] = {});
}

function getLastIndexInStack(stack, vScale, positive, type) {
  for (const meta of vScale.getMatchingVisibleMetas(type).reverse()) {