Using Angular/Ionic, how do I get my external JS file to show its function on the home.page.html within my app?

Question

So I have my index.html, home.page.html and js/externaljs file setup, but can't get the externaljs file to return my function specifically to an id="demo" link on my home.page.html so that it won't display on my app. Need help with the coding to target the return value from my function to the id=demo, I've tried most other options on Angular documentation, no luck...

Here's Code from home.page.html file:

<ion-header [translucent]="true">
  <ion-toolbar color="primary">
    <ion-title>
      RANDOM WORD Generator!
    </ion-title>
  </ion-toolbar>
</ion-header>

<ion-content [fullscreen]="false">
    <div id="container" class="ion-margin">
    <strong>RANDOM WORD GENERATOR</strong>
 
    <ion-card>
      <ion-card-header>
        <ion-card-title>RANDOM WORD:</ion-card-title>
      </ion-card-header>
      <ion-grid>
        <ion-row>
          <ion-col>
            <ul>
              <li>OR</li>
              <li>AND</li>
              <li>HIS</li>
            </ul>
            <p id="demo"></p>
          <ion-button color="dark" expand="full" (click)="CallExternalJSFileFunction()">Call External JS File Function</ion-button>

            <script src="./myplace/assets/js/swgenfile.js"></script>

          </ion-col>
        </ion-row>
      </ion-grid>

     
    </ion-card>
   
   </div>
</ion-content>

Here's swgenfile.js file:

var randomWord = [ ]
randomWord[0] = "or";
randomWord[1] = "is";
randomWord[2] = "he";
randomWord[3] = "she";
randomWord[4] = "his";
randomWord[5] = "their";
randomWord[6] = "day";

function randomWord () {
    var randomWordGen = Math.floor(Math.random()*(randomWord.length));
    document.getElementById('pSightWord').innerHTML = randomWord[randomWordGen];
}

Again, trying to get above files to communicate and place a random word in the "placeholder" within my Angular/Ionic app - but its not working obviously. Appreciate any help and input, sorry for the delay - been busy doing everything but learning coding - COVID!