discourse-custom-wizard/assets/javascripts/discourse/components/custom-wizard-field-time.js

import Component from "@ember/component";
import { observes } from "discourse-common/utils/decorators";

export default Component.extend({
  classNameBindings: ["fieldClass"],

  @observes("time")
  setValue() {
    this.set("field.value", this.time.format(this.field.format));
  },

  actions: {
    onChange(value) {
      this.set(
        "time",
        moment({
          hours: value.hours,
          minutes: value.minutes,
        })
      );
    },
  },
});