nitropage/src/features/editor/lib/element/findNextElementIds.ts

A free and open source, extensible visual page builder based on SolidStart.

import { State } from "../../../../../types";

/**
 * An element has different ids in different page revisions
 * This tries to find the ids when switching from one revision to another one
 */
export const findNextElementIds = (
  prevIds: (string | undefined)[],
  prevState: State,
  nextState: Partial<State>,
) => {
  let resultLength = 0;
  let result = {} as Record<string, string | null | undefined>;

  const historyCandidates = [] as [string, string][];
  const nextElements = nextState.elements!;

  for (const prevId of prevIds) {
    if (prevId == null) {
      resultLength++;
      continue;
    }

    if (nextElements[prevId] != null) {
      result[prevId] = prevId;
      resultLength++;
      continue;
    }

    const historyId = prevState.elements[prevId].historyId;
    if (!historyId) {
      resultLength++;
      continue;
    }

    historyCandidates.push([prevId, historyId]);
  }

  if (resultLength !== prevIds.length) {
    for (const nextElement of Object.values(nextElements)) {
      if (resultLength === prevIds.length) {
        break;
      }

      for (const [prevId, historyId] of historyCandidates) {
        if (result[prevId]) {
          continue;
        }
        if (nextElement.historyId != historyId) {
          continue;
        }

        result[prevId] = nextElement.id;
        resultLength++;
      }
    }
  }

  return prevIds.map((prevId) => (prevId && result[prevId]) ?? undefined);
};