src/virtual-scrolling-tree/VirtualScrollingTree.js
function expandItem(data) {
    // Cloning to avoid modification of the original data item.
    data = JSON.parse(JSON.stringify(data));

    if (!data.expansions) {
        data.expansions = [];
    }

    // Expansions are stored in a tree structure.
    let obj = findExpansion.call(this, data.parent);
    obj.expansions.push(data);
}
function expandItem(data) {
    // Cloning to avoid modification of the original data item.
    data = JSON.parse(JSON.stringify(data));

    if (!data.expansions) {
        data.expansions = [];
    }

    // Expansions are stored in a tree structure.
    let obj = findExpansion.call(this, data.parent);
    obj.expansions.push(data);
}
function expandItem ( data ) { // Cloning to avoid modification of the original data item. data = JSON . parse ( JSON . stringify ( data ) ) ; if ( ! data . expansions ) { data . expansions = [ ] ; } // Expansions are stored in a tree structure. let obj = findExpansion . call ( this , data . parent ) ; obj . expansions . push ( data ) ; }
Adds item to list of expansions.

@method expandItem
@private
@params {Object} data
Adds item to list of expansions .