Fix: Advanced format output with short offset name

src/plugin/timezone/index.js

@@ -12,33 +12,36 @@ const typeToPos = {
 // Cache time-zone lookups from Intl.DateTimeFormat,
 // as it is a *very* slow method.
 const dtfCache = {}
-const getDateTimeFormat = (timezone, options = {}) => {
- const timeZoneName = options.timeZoneName || 'short'
- const key = `${timezone}|${timeZoneName}`
- let dtf = dtfCache[key]
+const getDateTimeFormat = (timeZone) => {
+ /* Long output is always correct whatever the timezone.
+ * and whatever the locale, en-US / en-GB etc...
+ * We will extract the short version ourself
+ */
+ let dtf = dtfCache[timeZone]
  if (!dtf) {
  dtf = new Intl.DateTimeFormat('en-US', {
  hour12: false,
- timeZone: timezone,
+ timeZone,
  year: 'numeric',
  month: '2-digit',
  day: '2-digit',
  hour: '2-digit',
  minute: '2-digit',
  second: '2-digit',
- timeZoneName
+ timeZoneName: 'long'
  })
- dtfCache[key] = dtf
+
+ dtfCache[timeZone] = dtf
  }
  return dtf
 }
 
 export default (o, c, d) => {
  let defaultTimezone
 
- const makeFormatParts = (timestamp, timezone, options = {}) => {
+ const makeFormatParts = (timestamp, timezone) => {
  const date = new Date(timestamp)
- const dtf = getDateTimeFormat(timezone, options)
+ const dtf = getDateTimeFormat(timezone)
  return dtf.formatToParts(date)
  }
 
@@ -107,11 +110,21 @@ export default (o, c, d) => {
  return ins
  }
 
- proto.offsetName = function (type) {
+ proto.offsetName = function (type = 'short') {
  // type: short(default) / long
  const zone = this.$x.$timezone || d.tz.guess()
+ const cachedOffsetName = this.$x.$offsetName || {}
+ const cacheKey = `${zone}-${type}}`
+ if (cachedOffsetName[cacheKey]) {
+ return cachedOffsetName[cacheKey]
+ }
  const result = makeFormatParts(this.valueOf(), zone, { timeZoneName: type }).find(m => m.type.toLowerCase() === 'timezonename')
- return result && result.value
+ if (type === 'short') {
+ result.value = result.value.split(' ').map(v => v[0]).join('')
+ }
+ cachedOffsetName[cacheKey] = result.value
+ this.$x.$offsetName = cachedOffsetName
+ return result.value
  }
 
  const oldStartOf = proto.startOf

test/plugin/advancedFormat.test.js

@@ -124,6 +124,22 @@ it('Format offsetName z zzz', () => {
  expect(dayjs().format('zzz')).toBeDefined()
 })
 
+it('Format offsetName z zzz with Europe/Berlin timeZone', () => {
+ const dtz = dayjs().tz('Europe/Berlin')
+ expect(dtz.format('z')).toBe('CEST')
+ expect(dtz.format('zzz')).toBe('Central European Summer Time')
+ expect(dayjs().format('z')).toBeDefined()
+ expect(dayjs().format('zzz')).toBeDefined()
+})
+
+it('Format offsetName z zzz with Asia/Kolkata timeZone', () => {
+ const dtz = dayjs.tz('2012-03-11 01:59:59', 'Asia/Kolkata')
+ expect(dtz.format('z')).toBe('IST')
+ expect(dtz.format('zzz')).toBe('India Standard Time')
+ expect(dayjs().format('z')).toBeDefined()
+ expect(dayjs().format('zzz')).toBeDefined()
+})
+
 it('Skips format strings inside brackets', () => {
  expect(dayjs().format('[Q]')).toBe('Q')
  expect(dayjs().format('[Do]')).toBe('Do')