Function onDragOver

packages/react-aria/src/dnd/useDrop.ts:149–233

(e: DragEvent)

  };

  let onDragOver = (e: DragEvent) => {
    e.preventDefault();
    e.stopPropagation();

    let allowedOperations = getAllowedOperations(e);
    if (
      e.clientX === state.x &&
      e.clientY === state.y &&
      allowedOperations === state.allowedOperations
    ) {
      e.dataTransfer.dropEffect = state.dropEffect;
      return;
    }

    state.x = e.clientX;
    state.y = e.clientY;

    let prevDropEffect = state.dropEffect;

    // Update drop effect if allowed drop operations changed (e.g. user pressed modifier key).
    if (allowedOperations !== state.allowedOperations) {
      let allowedOps = allowedOperationsToArray(allowedOperations);
      let dropOperation = allowedOps[0];
      if (typeof options.getDropOperation === 'function') {
        let types = new DragTypes(e.dataTransfer);
        dropOperation = getDropOperation(
          allowedOperations,
          options.getDropOperation(types, allowedOps)
        );
      }
      state.dropEffect = DROP_OPERATION_TO_DROP_EFFECT[dropOperation] || 'none';
    }

    if (typeof options.getDropOperationForPoint === 'function') {
      let types = new DragTypes(e.dataTransfer);
      let rect = (e.currentTarget as HTMLElement).getBoundingClientRect();
      let dropOperation = getDropOperation(
        allowedOperations,
        options.getDropOperationForPoint(
          types,
          allowedOperationsToArray(allowedOperations),
          state.x - rect.x,
          state.y - rect.y
        )
      );
      state.dropEffect = DROP_OPERATION_TO_DROP_EFFECT[dropOperation] || 'none';
    }

    state.allowedOperations = allowedOperations;
    e.dataTransfer.dropEffect = state.dropEffect;

    // If the drop operation changes, update state and fire events appropriately.
    if (state.dropEffect === 'none' && prevDropEffect !== 'none') {
      fireDropExit(e);
    } else if (state.dropEffect !== 'none' && prevDropEffect === 'none') {
      fireDropEnter(e);
    }