@atlaskit/editor-plugin-show-diff/dist/es2019/pm-plugins/calculateDiff/groupChangesByBlock.js

ShowDiff plugin for @atlaskit/editor-core

/**
 * Finds the position range of the top-level block (direct child of doc) that contains `pos`.
 * Returns null if `pos` is at the doc boundary or outside the doc content.
 */
function getTopLevelBlockAt(doc, from, to) {
  return {
    from: doc.resolve(from).before(1),
    to: doc.resolve(to).after(1)
  };
}

/**
 * Groups all changes that fall within the same top-level block (direct child of doc)
 * and merges them into a single change spanning the full block in both old and new doc.
 */
export function groupChangesByBlock(changes, docA, docB) {
  const groups = new Map();
  for (const change of changes) {
    const blockA = getTopLevelBlockAt(docA, change.fromA, change.toA);
    const blockB = getTopLevelBlockAt(docB, change.fromB, change.toB);
    if (!groups.has(blockB.from)) {
      groups.set(blockB.from, {
        fromB: blockB.from,
        toB: blockB.to,
        fromA: blockA ? blockA.from : change.fromA,
        toA: blockA ? blockA.to : change.toA,
        changed: []
      });
    }
    const group = groups.get(blockB.from);
    if (group) {
      group.changed = [...group.changed, ...change.inserted, ...change.deleted];
    }
  }
  return Array.from(groups.values()).sort((a, b) => a.fromB - b.fromB).map(({
    fromA,
    toA,
    fromB,
    toB,
    changed
  }) => ({
    fromA,
    toA,
    fromB,
    toB,
    /**
     * We add all changes (both deleted and inserted) as that will
     * inform the calculateDiffDecorations function that changes should be rendered
     * (even if the change is only one of the two).
     */
    deleted: changed,
    inserted: changed
  }));
}