discourse/app/assets/javascripts/admin/addon/components/modal/staff-action-log-change.js

import Component from "@glimmer/component";
import { tracked } from "@glimmer/tracking";
import { action } from "@ember/object";
import { ajax } from "discourse/lib/ajax";

export default class AdminStaffActionLogComponent extends Component {
  @tracked diff;

  constructor() {
    super(...arguments);
    this.loadDiff();
  }

  @action
  async loadDiff() {
    const diff = await ajax(
      `/admin/logs/staff_action_logs/${this.args.model.staffActionLog.id}/diff`
    );
    this.diff = diff.side_by_side;
  }
}