react-native-ui-lib/typings/components/carousel/CarouselPresenter.js

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import _ from "lodash";
export function getChildrenLength(props) {
    const length = _.get(props, "children.length") || 0;
    return length;
}
export function calcOffset(props, state) {
    const { currentPage } = state;
    const { pageWidth, loop } = props;
    const actualCurrentPage = loop ? currentPage + 1 : currentPage;
    return pageWidth * actualCurrentPage;
}
export function calcPageIndex(offset, props) {
    const pagesCount = getChildrenLength(props);
    const { pageWidth, loop } = props;
    const pageIndexIncludingClonedPages = Math.round(offset / pageWidth);
    let actualPageIndex;
    if (loop) {
        actualPageIndex =
            (pageIndexIncludingClonedPages + (pagesCount - 1)) % pagesCount;
    }
    else {
        actualPageIndex = Math.min(pagesCount - 1, pageIndexIncludingClonedPages);
    }
    return actualPageIndex;
}
export function isOutOfBounds(offset, props) {
    const { pageWidth } = props;
    const length = getChildrenLength(props);
    const minLimit = 1;
    const maxLimit = (length + 1) * pageWidth - 1;
    return !_.inRange(offset, minLimit, maxLimit);
}
// todo: need to support more cases of page width in loop mode
export function calcCarouselWidth(props) {
    const { pageWidth, loop } = props;
    let length = getChildrenLength(props);
    length = loop ? length + 2 : length;
    return pageWidth * length;
}