added prettier and eslint for dev

lib/domUtils.ts

@@ -0,0 +1,32 @@
+export const addGlobalEventListener = (
+  type: string,
+  selector: string,
+  callback: (arg0: Event) => void,
+  options: boolean | AddEventListenerOptions,
+  parent = document
+): void => {
+  parent.addEventListener(
+    type,
+    (e: Event) => {
+      if (e != null && e.target != null) {
+        const el = e.target as Element
+        if (el.matches(selector)) callback(e)
+      }
+    },
+    options
+  )
+}
+
+export const qs = (
+  selector: string | keyof HTMLElementTagNameMap,
+  parent = document
+): Element => {
+  return parent.querySelector(selector)
+}
+
+export const qsa = (
+  selector: string | keyof HTMLElementTagNameMap,
+  parent = document
+): Element[] => {
+  return [...parent.querySelectorAll(selector)]
+}

lib/formatters.ts

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+export const formatCurrency = (
+  number: number,
+  currency: string,
+  locale: string | undefined = undefined
+): string => {
+  const CURRENCY_FORMATTER = new Intl.NumberFormat(locale, {
+    currency: currency,
+    style: 'currency'
+  })
+
+  return CURRENCY_FORMATTER.format(number)
+}
+
+export const formatNumber = (
+  number: number,
+  locale: string | undefined = undefined
+): string => {
+  const NUMBER_FORMATTER = new Intl.NumberFormat(locale)
+
+  return NUMBER_FORMATTER.format(number)
+}
+
+export const formatCompactNumber = (
+  number: number,
+  locale: string | undefined = undefined
+): string => {
+  const COMPACT_NUMBER_FORMATTER = new Intl.NumberFormat(locale, {
+    notation: 'compact'
+  })
+
+  return COMPACT_NUMBER_FORMATTER.format(number)
+}
+
+type DivisionsT = {
+  amount: number
+  name:
+    | 'year'
+    | 'years'
+    | 'quarter'
+    | 'quarters'
+    | 'month'
+    | 'months'
+    | 'week'
+    | 'weeks'
+    | 'day'
+    | 'days'
+    | 'hour'
+    | 'hours'
+    | 'minute'
+    | 'minutes'
+    | 'second'
+    | 'seconds'
+}
+const DIVISIONS: DivisionsT[] = [
+  { amount: 60, name: 'seconds' },
+  { amount: 60, name: 'minutes' },
+  { amount: 24, name: 'hours' },
+  { amount: 7, name: 'days' },
+  { amount: 4.34524, name: 'weeks' },
+  { amount: 12, name: 'months' },
+  { amount: Number.POSITIVE_INFINITY, name: 'years' }
+]
+export const formatRelativeDate = (
+  toDate: number,
+  fromDate: number = new Date().getSeconds(),
+  locale: string | undefined = undefined
+): string => {
+  const RELATIVE_DATE_FORMATTER = new Intl.RelativeTimeFormat(locale, {
+    numeric: 'auto'
+  })
+  let duration = (toDate - fromDate) / 1000
+
+  for (let i = 0; i <= DIVISIONS.length; i++) {
+    const division = DIVISIONS[i]
+    if (Math.abs(duration) < division.amount)
+      return RELATIVE_DATE_FORMATTER.format(Math.round(duration), division.name)
+
+    duration /= division.amount
+  }
+}

lib/index.ts

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+export { sleep } from './utils.js'
+export { qsa, qs, addGlobalEventListener } from './domUtils.js'
+export {
+  formatCompactNumber,
+  formatNumber,
+  formatCurrency,
+  formatRelativeDate
+} from './formatters.js'

lib/utils.ts

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+export const sleep = (time: number): Promise<unknown> => {
+  return new Promise((resolve) => setTimeout(resolve, time))
+}