Function createKeyGetter

src/animation/universalTransition.ts:299–314

(isOld: boolean, onlyGetId: boolean)

    }

    function createKeyGetter(isOld: boolean, onlyGetId: boolean) {
        return function (diffItem: DiffItem): string {
            const data = diffItem.data;
            const dataIndex = diffItem.dataIndex;
            // TODO if specified dim
            if (onlyGetId) {
                return data.getId(dataIndex);
            }
            if (isOld) {
              return direction === TRANSITION_P2C ? diffItem.childGroupId : diffItem.groupId;
            }
            else {
              return direction === TRANSITION_C2P ? diffItem.childGroupId : diffItem.groupId;
            }
        };
    }

    // Use id if it's very likely to be an one to one animation
    // It's more robust than groupId