react-virtualized/dist/commonjs/Grid/utils/calculateSizeAndPositionDataAndUpdateScrollOffset.js

React components for efficiently rendering large, scrollable lists and tabular data

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports["default"] = calculateSizeAndPositionDataAndUpdateScrollOffset;
/**
 * Helper method that determines when to recalculate row or column metadata.
 */
/*:: type Params<T> = {
  // Number of rows or columns in the current axis
  cellCount: number,

  // Width or height of cells for the current axis
  cellSize: ?number,

  // Method to invoke if cell metadata should be recalculated
  computeMetadataCallback: (props: T) => void,

  // Parameters to pass to :computeMetadataCallback
  computeMetadataCallbackProps: T,

  // Newly updated number of rows or columns in the current axis
  nextCellsCount: number,

  // Newly updated width or height of cells for the current axis
  nextCellSize: ?number,

  // Newly updated scroll-to-index
  nextScrollToIndex: number,

  // Scroll-to-index
  scrollToIndex: number,

  // Callback to invoke if the scroll position should be recalculated
  updateScrollOffsetForScrollToIndex: () => void,
};*/
function calculateSizeAndPositionDataAndUpdateScrollOffset(_ref /*:: */) {
  var cellCount = _ref /*:: */.cellCount,
    cellSize = _ref /*:: */.cellSize,
    computeMetadataCallback = _ref /*:: */.computeMetadataCallback,
    computeMetadataCallbackProps = _ref /*:: */.computeMetadataCallbackProps,
    nextCellsCount = _ref /*:: */.nextCellsCount,
    nextCellSize = _ref /*:: */.nextCellSize,
    nextScrollToIndex = _ref /*:: */.nextScrollToIndex,
    scrollToIndex = _ref /*:: */.scrollToIndex,
    updateScrollOffsetForScrollToIndex = _ref /*:: */.updateScrollOffsetForScrollToIndex;
  // Don't compare cell sizes if they are functions because inline functions would cause infinite loops.
  // In that event users should use the manual recompute methods to inform of changes.
  if (cellCount !== nextCellsCount || (typeof cellSize === 'number' || typeof nextCellSize === 'number') && cellSize !== nextCellSize) {
    computeMetadataCallback(computeMetadataCallbackProps);

    // Updated cell metadata may have hidden the previous scrolled-to item.
    // In this case we should also update the scrollTop to ensure it stays visible.
    if (scrollToIndex >= 0 && scrollToIndex === nextScrollToIndex) {
      updateScrollOffsetForScrollToIndex();
    }
  }
}