error

vue.esm.js?efeb:578 [Vue warn]: Property or method "comments" is not defined on the instance but referenced during render. Make sure that this property is reactive, either in the data option, or for class-based components, by initializing the property. See: https://vuejs.org/v2/guide/reactivity.html#Declaring-Reactive-Properties.

found in

---> <Comments> at src/components/Comments.vue
       <Root>
warn @ vue.esm.js?efeb:578
warnNonPresent @ vue.esm.js?efeb:1875
get @ vue.esm.js?efeb:1918
render @ Comments.vue?4eb8:17
Vue._render @ vue.esm.js?efeb:4474
updateComponent @ vue.esm.js?efeb:2765
get @ vue.esm.js?efeb:3115
Watcher @ vue.esm.js?efeb:3104
mountComponent @ vue.esm.js?efeb:2772
Vue$3.$mount @ vue.esm.js?efeb:8429
Vue$3.$mount @ vue.esm.js?efeb:10790
init @ vue.esm.js?efeb:4065
createComponent @ vue.esm.js?efeb:5512
createElm @ vue.esm.js?efeb:5460
createChildren @ vue.esm.js?efeb:5586
createElm @ vue.esm.js?efeb:5488
patch @ vue.esm.js?efeb:6034
Vue._update @ vue.esm.js?efeb:2637
updateComponent @ vue.esm.js?efeb:2765
get @ vue.esm.js?efeb:3115
Watcher @ vue.esm.js?efeb:3104
mountComponent @ vue.esm.js?efeb:2772
Vue$3.$mount @ vue.esm.js?efeb:8429
Vue$3.$mount @ vue.esm.js?efeb:10790
Vue._init @ vue.esm.js?efeb:4570
Vue$3 @ vue.esm.js?efeb:4659
(anonymous) @ main.js?1c90:7
(anonymous) @ main.js:16
./src/main.js @ app.js:1626
__webpack_require__ @ app.js:679
fn @ app.js:89
0 @ app.js:1675
__webpack_require__ @ app.js:679
(anonymous) @ app.js:725
(anonymous) @ app.js:728
vue.esm.js?efeb:578 [Vue warn]: Error in mounted hook: "TypeError: this.getComments is not a function"

found in

---> <Comments> at src/components/Comments.vue
       <Root>
warn @ vue.esm.js?efeb:578
logError @ vue.esm.js?efeb:1713
globalHandleError @ vue.esm.js?efeb:1708
handleError @ vue.esm.js?efeb:1697
callHook @ vue.esm.js?efeb:2897
insert @ vue.esm.js?efeb:4090
invokeInsertHook @ vue.esm.js?efeb:5864
patch @ vue.esm.js?efeb:6083
Vue._update @ vue.esm.js?efeb:2637
updateComponent @ vue.esm.js?efeb:2765
get @ vue.esm.js?efeb:3115
Watcher @ vue.esm.js?efeb:3104
mountComponent @ vue.esm.js?efeb:2772
Vue$3.$mount @ vue.esm.js?efeb:8429
Vue$3.$mount @ vue.esm.js?efeb:10790
Vue._init @ vue.esm.js?efeb:4570
Vue$3 @ vue.esm.js?efeb:4659
(anonymous) @ main.js?1c90:7
(anonymous) @ main.js:16
./src/main.js @ app.js:1626
__webpack_require__ @ app.js:679
fn @ app.js:89
0 @ app.js:1675
__webpack_require__ @ app.js:679
(anonymous) @ app.js:725
(anonymous) @ app.js:728
vue.esm.js?efeb:1717 TypeError: this.getComments is not a function
    at VueComponent.mounted (Comments.vue?037b:37)
    at callHook (vue.esm.js?efeb:2895)
    at Object.insert (vue.esm.js?efeb:4090)
    at invokeInsertHook (vue.esm.js?efeb:5864)
    at Vue$3.patch [as __patch__] (vue.esm.js?efeb:6083)
    at Vue$3.Vue._update (vue.esm.js?efeb:2637)
    at Vue$3.updateComponent (vue.esm.js?efeb:2765)
    at Watcher.get (vue.esm.js?efeb:3115)
    at new Watcher (vue.esm.js?efeb:3104)
    at mountComponent (vue.esm.js?efeb:2772)