budibase/packages/client/src/store/notification.js

import { writable } from "svelte/store"

const NOTIFICATION_TIMEOUT = 3000

const createNotificationStore = () => {
	const timeoutIds = new Set();
  const _notifications = writable([], () => {
		return () => {
			// clear all the timers
			timeoutIds.forEach(timeoutId => {
				clearTimeout(timeoutId);
			});
			_notifications.set([]);
		}
	});

  const send = (message, type = "default") => {
		let _id = id();
    _notifications.update(state => {
      return [...state, { id: _id, type, message }]
    });
		const timeoutId = setTimeout(() => {
			_notifications.update(state => {
				return state.filter(({ id }) => id !== _id);
			});
		}, NOTIFICATION_TIMEOUT);
		timeoutIds.add(timeoutId);
	}

  const { subscribe } = _notifications

  return {
    subscribe,
    send,
    danger: msg => send(msg, "danger"),
    warning: msg => send(msg, "warning"),
    info: msg => send(msg, "info"),
    success: msg => send(msg, "success"),
  }
}

function id() {
  return '_' + Math.random().toString(36).substr(2, 9);
};

export const notificationStore = createNotificationStore()