export default {    install(vue, options) {        console.log(vue);        console.log(options);        // vue.add()        vue.add = function foo(a, b) {            console.log('add result is :', a + b);        };        // this.reduce()        vue.prototype.reduce = function bar(a, b) {            console.log('reduce:', a - b);        };        vue.directive('form', {            acceptStatement: true,            bind(el, binding, vnode, oldVnode) {                // 获取绑定的元素，节点。。。                console.log('bind', el, binding, vnode, oldVnode);            },            unbind() {                console.log('unbind');            },            update(fn) {                console.log('fn is ', fn);            },        });        // mixin 混合created()        vue.mixin({            created() {                console.log('组件开始加载');            }        });    },};