import { _flattenChildren } from "./createElement";export const Children = {    only(children) {        //only方法接受的参数只能是一个对象，不能是多个对象（数组）。        if (Array.isArray(children)) {            children = children[0];        }        if (children && children.vtype) {            return children;        }        throw new Error("expect only one child");    },    count(children) {        return _flattenChildren(children, false).length;    },    forEach(children, callback, context) {        _flattenChildren(children, false).forEach(callback, context);    },    map(children, callback, context) {        return _flattenChildren(children, false).map(callback, context);    },    toArray: function (children) {        return _flattenChildren(children, false);    }};