Function getTransformDiff

packages/2d/src/lib/utils/diff.ts:54–99

(
  from: T[],
  to: T[],
)

}

export function getTransformDiff<T extends Idable>(
  from: T[],
  to: T[],
): TransformDiff<T> {
  const diff: TransformDiff<T> = {
    inserted: [],
    deleted: [],
    transformed: [],
  };

  const fromMap = getIdMap(from);
  const toMap = getIdMap(to);

  for (const [key, fromItem] of fromMap.entries()) {
    const toItem = toMap.get(key);
    if (toItem) {
      toMap.delete(key);
      for (let i = 0; i < Math.max(fromItem.length, toItem.length); i++) {
        const insert = i >= fromItem.length;
        const remove = i >= toItem.length;

        const fromNode = !insert ? fromItem[i] : fromItem[fromItem.length - 1];
        const toNode = !remove ? toItem[i] : toItem[toItem.length - 1];

        diff.transformed.push({
          insert,
          remove,
          from: fromNode,
          to: toNode,
        });
      }
    } else {
      for (const node of fromItem) {
        diff.deleted.push(node);
      }
    }
  }

  for (const toItem of toMap.values()) {
    for (const node of toItem) {
      diff.inserted.push(node);
    }
  }

  return diff;
}

export function applyTransformDiff<T extends Idable>(
  current: T[],