removeChild(node, child) {
        if (!node.children) return;
        if (typeof child === 'string') {
            _.remove(node.children, { name: child });
        } else {
            const index = node.children.indexOf(child);
            if (index >= 0) node.children.splice(index, 1);
        }
    }
Remove a child node.
@param {{}} node - The parent node.
@param {string|{}} child - The child node or name of node.
@returns {undefined}