Simple clock experiment in Vue that isn't quite working...

Clock.ts

export class Clock {

    TickTimeout: number = 50;
    TickCallback!: Function;
    IsPaused: boolean = false;

    LastTickTime!: number;

    Start(tickCallback?:Function) {
        if (tickCallback !== undefined) {
            this.TickCallback = tickCallback;
        } else { 
            this.TickCallback = () => { };
        }

        this.LastTickTime = performance.now();
        this.Tick();
    }

    Tick(): number {
        var now = performance.now();
        var deltaMs = now - this.LastTickTime;
        this.LastTickTime = now;

        setTimeout(this.Tick, this.TickTimeout);
        this.TickCallback(deltaMs);
        return deltaMs;
    }

}

ClockDisplay.vue

<!-- src/components/ClockDisplay.vue -->

<template>
    <div id="clock-display-container">
        Tick History: {{ tickHistory }}
    </div>
</template>

<script lang="ts">
    import { Vue, Component, Prop } from "vue-property-decorator";

    @Component
    export default class ClockDisplay extends Vue {
        @Prop() tickHistory!: number[];
    }
</script>

<style lang="scss">
</style>

ClockHistory.ts

export class ClockHistory {

    TickHistory: number[] = [];

    Tick(deltaMs:number){
        this.TickHistory.push(deltaMs);
    }
}

Core.vue

<!-- src/components/GameCore.vue -->

<template>
    <div id="container">
        <ClockDisplay :tickHistory="ClockHistory.TickHistory"/>
    </div>
</template>

<script lang="ts">
    import { Clock } from "../classes/Clock";
    import { ClockHistory } from "../classes/ClockHistory";

    import { Vue, Component, Prop } from "vue-property-decorator";
    import ClockDisplay from "./ClockDisplay.vue";

    @Component({ 
        components: { 
            ClockDisplay 
            }
        }
    )
    export default class Core extends Vue {

        Clock!: Clock;
        ClockHistory!: ClockHistory;

        created() {
            this.Clock = new Clock();
            this.ClockHistory = new ClockHistory();
            
            this.Clock.Start(this.ClockHistory.Tick);
        }
    } 
</script>

<style lang="scss">
</style>

errors.txt

10:27:20.082 [Vue warn]: Error in created hook: "TypeError: this.TickHistory is undefined"

found in

---> <Core> at src/components/Core.vue
       <Root> vue.esm.js:591
10:27:20.083 TypeError: "this.TickHistory is undefined"
Tickwebpack-internal:///./src/classes/ClockHistory.ts:8:9Tickwebpack-internal:///./src/classes/Clock.ts:22:9Startwebpack-internal:///./src/classes/Clock.ts:15:9createdwebpack-internal:///./node_modules/ts-loader/index.js?!./node_modules/vue-loader/lib/index.js?!./src/components/Core.vue?vue&type=script&lang=ts&:37:9callHookwebpack-internal:///./node_modules/vue/dist/vue.esm.js:2920:9_initwebpack-internal:///./node_modules/vue/dist/vue.esm.js:4618:5VueComponentwebpack-internal:///./node_modules/vue/dist/vue.esm.js:4786:7createComponentInstanceForVnodewebpack-internal:///./src/node_modules/vue/dist/vue.esm.js:4305:10initwebpack-internal:///./src/node_modules/vue/dist/vue.esm.js:4126:45createComponentwebpack-internal:///./src/node_modules/vue/dist/vue.esm.js:5596:9createElmwebpack-internal:///./src/node_modules/vue/dist/vue.esm.js:5543:9patchwebpack-internal:///./src/node_modules/vue/dist/vue.esm.js:6118:9_updatewebpack-internal:///./src/node_modules/vue/dist/vue.esm.js:2659:16updateComponentwebpack-internal:///./src/node_modules/vue/dist/vue.esm.js:2787:7getwebpack-internal:///./src/node_modules/vue/dist/vue.esm.js:3141:13Watcherwebpack-internal:///./src/node_modules/vue/dist/vue.esm.js:3130:7mountComponentwebpack-internal:///./src/node_modules/vue/dist/vue.esm.js:2794:3mountwebpack-internal:///./src/node_modules/vue/dist/vue.esm.js:8528:10mountwebpack-internal:///./src/node_modules/vue/dist/vue.esm.js:10927:10_initwebpack-internal:///./src/node_modules/vue/dist/vue.esm.js:4628:7Vuewebpack-internal:///./src/node_modules/vue/dist/vue.esm.js:4717:3<anonymous>webpack-internal:///./src/index.ts:7:9tsfile:///D:/Projects/Programming/FormicariumJS/dist/build.js:436:1__webpack_require__file:///D:/Projects/Programming/FormicariumJS/dist/build.js:20:12<anonymous>file:///D:/Projects/Programming/FormicariumJS/dist/build.js:84:18<anonymous>file:///D:/Projects/Programming/FormicariumJS/dist/build.js:1:11 vue.esm.js:1741
10:27:20.121 You are running Vue in development mode.
Make sure to turn on production mode when deploying for production.
See more tips at https://vuejs.org/guide/deployment.html vue.esm.js:8566
10:27:20.122 You are running Vue in development mode.
Make sure to turn on production mode when deploying for production.
See more tips at https://vuejs.org/guide/deployment.html vue.esm.js:8566
10:27:20.149 [Show/hide message details.] TypeError: this.TickCallback is not a function[Learn More] build.js line 316 > eval:22:9

index.html

<!doctype html>
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
</head>

<body>
    <div id="app"></div>
</body>
<script src="./dist/build.js"></script>

</html>

index.ts

// src/index.ts
import Vue from "vue";
import Core from "./components/Core.vue";

let v = new Vue({
    el: "#app",
    template: 
        `<Core />`,
    propsData: { 
    },
    components: {
        Core,
    }
});