大神，点击按钮报viewer无定义，请帮忙看看吧

[loooon]

bundle.js:11910 [Vue warn]: Error in v-on handler: "TypeError: Cannot read property 'viewer' of undefined"

found in

---> at src/components/subcomponents/Enlarge.vue
at src/components/ribbon/StartContainer.vue
at src/components/App.vue

warn @ bundle.js:11910
logError @ bundle.js:13175
globalHandleError @ bundle.js:13170
handleError @ bundle.js:13130
invokeWithErrorHandling @ bundle.js:13153
invoker @ bundle.js:13470
original._wrapper @ bundle.js:18208
bundle.js:13179 TypeError: Cannot read property 'viewer' of undefined
at VueComponent.enlarge (bundle.js:76346)
at invokeWithErrorHandling (bundle.js:13145)
at HTMLAnchorElement.invoker (bundle.js:13470)
at HTMLAnchorElement.original._wrapper (bundle.js:18208)