javascript-time-ago
International higly customizable relative date/time formatter (both for past and future dates).
Formats a date to something like:
- just now
- 5m
- 15 min
- 25 minutes
- half an hour ago
- an hour ago
- 2h
- yesterday
- 2d
- 1wk
- 2 weeks ago
- 3 weeks
- half a month ago
- 1 mo. ago
- 2 months
- half a year
- a year
- 2yr
- 5 years ago
- … or whatever else
Usage
npm install javascript-time-ago --save
First, the library must be initialized with a set of desired locales.
import TimeAgo from 'javascript-time-ago'
import en from 'javascript-time-ago/locale/en'
import ru from 'javascript-time-ago/locale/ru'
TimeAgo.locale(en)
TimeAgo.locale(ru)
After the initialization step is complete it is ready to format relative dates.
import TimeAgo from 'javascript-time-ago'
const timeAgo = new TimeAgo('en-US')
timeAgo.format(new Date())
timeAgo.format(Date.now() - 60 * 1000)
timeAgo.format(Date.now() - 2 * 60 * 60 * 1000)
timeAgo.format(Date.now() - 24 * 60 * 60 * 1000)
import TimeAgo from 'javascript-time-ago'
const timeAgo = new TimeAgo('ru-RU')
timeAgo.format(new Date())
timeAgo.format(Date.now() - 60 * 1000)
timeAgo.format(Date.now() - 2 * 60 * 60 * 1000)
timeAgo.format(Date.now() - 24 * 60 * 60 * 1000)
Mimics Twitter style of time ago ("1m", "2h", "Mar 3", "Apr 4, 2012")
…
const timeAgo = new TimeAgo('en-US')
timeAgo.format(new Date(), 'twitter')
timeAgo.format(Date.now() - 60 * 1000, 'twitter')
timeAgo.format(Date.now() - 2 * 60 * 60 * 1000, 'twitter')
The built-in Twitter style uses Intl
internally for formatting day/month/year
labels. This is not an issue for modern web browsers but requies Intl
polyfill for a couple of older browsers and for Node.js (if you're running this code on server side). See the Intl
section of this document for Intl
polyfill instructions. When Intl
is not available Twitter style falls back to the default one.
"Just time" style
timeAgo.format(new Date(), 'time')
Similar to the default style but with "ago" omitted:
- just now
- 1 minute
- 2 minutes
- 5 minutes
- 10 minutes
- 15 minutes
- 20 minutes
- half an hour
- 1 hour
- 2 hours
- …
- 20 hours
- 1 day
- 2 days
- 3 days
- 4 days
- 5 days
- 1 week
- 2 weeks
- 3 weeks
- 1 month
- 2 months
- 3 months
- 4 months
- half a year
- 1 year
- 2 years
- 3 years
- …
Loading locales
No locale data is loaded by default: a developer must manually choose which locales must be loaded. This is to reduce the resulting javascript bundle size.
If the resulting bundle size is of no concern (e.g. a big enterprise application), or if the code is being run on server side, then use this helper to load all available locales:
require('javascript-time-ago/load-all-locales')
RelativeTimeFormat
There's a spec proposal called Intl.RelativeTimeFormat
suggesting web browsers implement "time ago" formatting natively like they already do for dates and numbers. It's still a draft, and not officially accepted yet, but I guess at some point in time it will be accepted, in which case this library could serve as a polyfill for older browsers (iOS, Android).
import JavascriptTimeAgo, { RelativeTimeFormat } from 'javascript-time-ago'
import en from 'javascript-time-ago/locale/en'
JavascriptTimeAgo.locale(en)
new RelativeTimeFormat('en').format(-2, 'day')
Advanced
The above sections explained all the basics required for using this library in a project.
This part of the documentation contains some advanced topics for those willing to have a better understanding of how this library works internally.
Customization
Localization can be further customized by selecting one of the "flavours": long
, short
, or mabe some others (like tiny
defined for en
). Refer to locale/en
for an example.
import english from 'javascript-time-ago/locale/en'
english.tiny
english.short
english.long
One can pass style
(string
or object
) as a second parameter to the .format(date, style)
function. The style
object can specify (all are optional):
flavour
– preferred labels variant (e.g. short
, long
)units
– a list of time interval measurement units which can be used in the formatted output (e.g. ['second', 'minute', 'hour']
)gradation
– custom time interval measurement units scalecustom
– a function of { elapsed, time, date, now, locale }
. If this function returns a value, then the .format()
call will return that value. Otherwise the date/time is formatted as usual.
(see twitter
style for an example)
Gradation
A gradation
is a list of time interval measurement steps. A simple example:
[
{
unit: 'second',
},
{
unit: 'minute',
factor: 60,
threshold: 59.5
},
{
unit: 'hour',
factor: 60 * 60,
threshold: 59.5 * 60
},
…
]
factor
is a divider for the supplied time interval (in seconds)threshold
is a minimum time interval value (in seconds) required for this gradation step- (some advanced
threshold
customization is possible, see ./source/gradation.js
for more info) granularity
can also be specified (for example, 5
for minute
to allow only 5-minute intervals)
For more gradation examples see source/gradation.js
Built-in gradations:
import { gradation } from 'javascript-time-ago'
gradation.canonical()
gradation.convenient()
Localization internals
The localization resides in the locale
folder.
The format a localization is:
{
…
"day":
{
"past":
{
"one": "{0} day ago",
"other": "{0} days ago"
},
"future":
{
"one": "in {0} day",
"other": "in {0} days"
}
},
…
}
The past
and future
can be defined by any of: zero
, one
, two
, few
, many
and other
. For more info on which is which read the official Unicode CLDR documentation. Unicode CLDR (Common Locale Data Repository) is an industry standard and is basically a collection of formatting rules for all locales (date, time, currency, measurement units, numbers, etc).
To determine whether a certain amount of time (number) is one
, few
, or something else, javascript-time-ago
uses Unicode CLDR rules for formatting plurals. These rules are number quantifying functions (one for each locale) which can tell if a number should be treated as zero
, one
, two
, few
, many
or other
. Knowing how these pluralization rules work is not required but anyway here are some links for curious advanced readers: rules explanation, list of rules for all locales, converting those rules to javascript functions. These quantifying functions can be found as quantify
properties of a locale data.
Future
When given future dates .format()
produces the corresponding output, e.g. "in 5 minutes", "in a year", etc.
Default
The default locale is en
and can be changed: TimeAgo.defaultLocale = 'ru'
.
React
There is also a React component built upon this library which autorefreshes itself.
Intl
Intl
global object is not required for this library, but it may be required if you choose to use the built-in twitter
style (though it will fall back to the default style if Intl
is not available).
Intl
is present in all modern web browsers and is absent from some of the old ones: Internet Explorer 10, Safari 9 and iOS Safari 9.x (which can be solved using Intl
polyfill).
Node.js starting from 0.12
has Intl
built-in, but only includes English locale data by default. If your app needs to support more locales than English on server side then you'll need to use Intl
polyfill.
Applying Intl
polyfill:
npm install intl@1.2.4 --save
npm install intl-locales-supported --save
Node.js
import IntlPolyfill from 'intl'
import intlLocalesSupported from 'intl-locales-supported'
if (typeof Intl === 'object') {
if (!intlLocalesSupported(['ru', 'fr', ...])) {
Intl.NumberFormat = IntlPolyfill.NumberFormat
Intl.DateTimeFormat = IntlPolyfill.DateTimeFormat
}
}
else {
global.Intl = IntlPolyfill
}
Web browser: only download intl
package if the web browser doesn't support it, and only download the required locale.
async function initIntl() {
if (typeof Intl === 'object') {
return
}
await Promise.all([
import('intl'),
import('intl/locale-data/jsonp/en')
])
}
initIntl().then(...)
Contributing
After cloning this repo, ensure dependencies are installed by running:
npm install
This module is written in ES6 and uses Babel for ES5
transpilation. Widely consumable JavaScript can be produced by running:
npm run build
Once npm run build
has run, you may import
or require()
directly from
node.
After developing, the full test suite can be evaluated by running:
npm test
When you're ready to test your new functionality on a real project, you can run
npm pack
It will build
, test
and then create a .tgz
archive which you can then install in your project folder
npm install [module name with version].tar.gz
License
MIT