Export

let model = await SketchUpApi.getActiveModel();
// Now the data URL string in the format 'data:application/vnd.sketchup.skp;base64,...'
// can be used for downloading, saving, or transferring the model file.
let skpDataUrl = await model.getSkp();

Export Excluding Hidden Geometry

let model = await SketchUpApi.getActiveModel();
let tagManager = await model.getTagManager();

function createHiddenTagFilter(tagManager) {
    const hiddenTags = [];
    const addHiddenTags = (tagFolder, parentHidden) => {
        const folderHidden = parentHidden || !tagFolder.visible;
        tagFolder.tags.forEach((tag) => {
            if (folderHidden) hiddenTags.push(tag);
        });
        tagFolder.tagFolders.forEach((subFolder) => {
            addHiddenTags(subFolder, folderHidden);
        });
    };
    tagManager.tags.forEach((tag) => {
        if (!tag.visible) hiddenTags.push(tag);
    });
    tagManager.tagFolders.forEach((tagFolder) => {
        addHiddenTags(tagFolder, false);
    });
    return { tags: hiddenTags };
}

let hiddenElementsFilter = {
    or: [
        { visible: false },
        createHiddenTagFilter(tagManager)
    ],
};

await model.performOperation(async (op) => {
    const invisible = await model.entities.get({filterBy: hiddenElementsFilter});
    invisible.forEach(entity => op.drawingElementEraseWithForce(entity));
    op.purgeUnusedDefinitions();

    for(const component of (await model.getDefinitions())) {
        const invisible = await component.entities.get({filterBy: hiddenElementsFilter});
        invisible.forEach(entity => op.drawingElementEraseWithForce(entity));
    }

    // seconds purge
    op.purgeUnusedDefinitions();
    op.purgeUnusedMaterials();
}, 'Delete hidden entities');

let exportedData = await model.getSkp();

if (model.revision !== (await model.refresh()).revision) {
  await model.undo();
}