vue-父子组件生命周期顺序

在创建页面时：父组件在挂载前，要让子组件先挂载，
父beforeCreate => 父created => 父beforeMount => 子beforeCreate => 子created =>子beforeMount => 子Mounted=>父Mounted
在跟新时：父组件要在跟新前等子组件跟新
父beforeUpdate =>子beforeUpdate => 子updated => 父updated