Modularize moment.js, make the core as light as possible

[srcspider]

I remember when moment was a "lightweight" library, right now at 12kb (gziped no less) for, what it's in most cases, just very very simple date manipulation.

A simple solution to this problem would be to modularize momentjs so at least for environments like browerify, webpack and such a minimal version can be obtained.

eg.

Regular usage can stay the same,

// get everything under the sun
var moment = require('moment');

Modular usage could look like this,

// get core, the core does nothing, no validation, no nothing
// it would only define a internal storage structure and the bare minimum
// methods for getting values out of it: day, month, year, etc (no "format" 
// functions or "fromNow" since you might not even want to use them)
var moment = require('moment/core');

// add plugins for all the stuff you need, if you ever want ALL of them you 
// just include the directory instead (node/browserify/webpack will pick up
// a index.js inside it that would have all the things)
moment.plugin([

    // if you know this is all the parsers you need this is all you add
    require('moment/plugins/parser/yyyy-mm-dd-time'),
    require('moment/plugins/parser/unixtime'),

    require('moment/plugins/validator/yyyy-mm-dd-time'),
    // if we don't use unixtime locally, only on server we dont care for that
    // when it comes to validation

    require('moment/plugins/fromNow'),
    require('moment/plugins/toUnixTime'),

    // with a modular structure we can add 3rd party stuff really easily
    require('moment-phpstyle-format'),
    require('moment-chained-functions-format')

]);

// lock in the configuration so that calling plugin method throw and exception
// this would be irreversible but you can get a unlocked version by calling copy
// this will force people to get a "copy" of the configuration before doing 
// anything stupid -- or help them find the mistake if they add it later
moment.lock();

// you now just include this file where you need it
module.exports = moment;

Let's pretend the above is in something like lib/moment and represents your default boilerplate configuration for it. Obviously you may eventually encounter situations where you need more advanced functions. If we add to the default boilerplate we unfortunately add to every other context that doesn't need it. This is a big bummer if we're trying to keep client size down with things like webpack code splitting.

However, so long as the modular system is capable of being extending any time there's no problem whatsoeve. Ideally, to avoid subtle race condition bugs, we should be able to get a new "advanced" version as a separate instance:

// load boilerplate we defined previously
// we request a copy of the instance so no funny business happens
var moment = require('lib/moment').copy(); 

// we can also create a separate boilerplate if we re-use this a lot
moment.plugin(require('expensive-internationalization-timezone-nonsense'));
moment.lock(); // lock the new copy just in case its passed around

// moment instances should be able to do a quick copy between instances
// to ensure functionality, ie. moment(createdAt) could just swap plugin pointers

Now only the module that actually uses that feature pays the cost. If you use moment in 100 places and only 1 actually needs internationalization just that one place will ever pay for it. This applies to all functions, all the core needs to do is store a plain date object and some getters. Is everything you do just pass unix time from the server? you can just have unixtime parser. Do you only ever validate dates on the server? you can skip on any and all validation, etc.

It's effectively as light as you building your own specialized helpers. And much like projects like gulp, postcss and so on the community can contribute easily to it though easily maintainable chunks.

And in this way, momentjs can, once again, be called "lightweight javascript date library".

[naartjie]

right now at 12kb (gziped no less)

Are you using the version from CDN or npm? My size increase is more like 48kb gzipped. #2416

[srcspider]

@naartjie

You'll want to use webpack's ignore plugin (sorry cant recall name of the top of my head) to exclude locale information. That should bring it down to something more reasonable.

48kb gzip is indeed pretty crazy, my largest entry point (react + various util functions + application code for full rendering) sits at around 50kb gzip. I've switched to just using unix timestamps and completely custom functions to process those into a format as needed... a bit sad, would love to use a date manipulation library but just can't take a +100% initial load javascript bump. It's obviously even worse on subsequent incremental loads (caused by require.ensure) since those average at 10kb gzip as it's mostly application specific code, so should initial load avoid dates but one of those require dates then that's a 6x size increase.

[naartjie]

Thanks for the rundown @srcspider, I have read about IgnorePlugin before, but I didn't click that it was applicable for these kinds of situations, so it helps to match theory and practical together 👍

Does anyone need a library that gets bigger and bigger?

Don't you want to edit that line out? It might seem a little too brash, where as I think your general tone of the issue is very helpful, and you have a valid point. Plus you seem to know how this should all go down, I think a PR would go down well, I hear they're looking for help. ;-)

[naartjie]

I think it would be great to have the option to require a version with or without locales, that would be good at least for a start, and probably not too massive a refactor. I could have a stab at a PR. What say you @srcspider, do you think that would be useful to anyone else?

I know it's a 👍 from me, but I'm not sure if there would be any other takers out there.

[srcspider]

@naartjie not to be the bearer of bad news but would probably recommend waiting on one of the owners to give their thoughts on this before putting any considerable effort in. No point in pushing only to be shot down (or never approved). However if you need it yourself right now, by all means.

Plus you seem to know how this should all go down, I think a PR would go down well, I hear they're looking for help. ;-)

Sadly I'm very much on the fence on ES6. It doesn't integrate with my current workflows, and can't see any advantage to the various recommendations of ES6 workflows I've encountered (and by "no advantage" what I mean is they're far far inferior in resulting size, architecture and just a lot more unnecessarily complex in general).

It's hard to get exited to contributing to a "Port to ES6" when it's, overall, just a worse thing (for me).

[ichernev]

The port to es6 is supposed to benefit development, not users. There are packaged versions of moment, with and without locales, uploaded to npmjs.

About making a small core that is extensible - that is going to be a big step back in usability for most users. If you feel like it patch the src/moment to include what you want and transpile.

I'm closing this for now. If a moment without locales is not bundled properly feel free to reopen.

[naartjie]

There are packaged versions of moment, with and without locales, uploaded to npmjs

@ichernev I tried looking, and all I found was moment and moment-timezone, could you point me to the version of moment without locales in npmjs.

I actually asked for this in #2416. It feels like using the IgnorePlugin is a hack/workaround, if there is already a packaged version without locales.

Thanks.

[ichernev]

Aaah, I see. Npmjs is historically used for server side, where you don't care about size. But for other build tools that go on top of it, I guess we shall add another target moment-core or something like this.

[naartjie]

That would be great, thanks @ichernev. It will make integrating with tools like webpack a breeze (without needing the likes of IgnorePlugin).

I see you've reopened this one, so I'm going to close #2416 again ;-)

[fresheneesz]

@ichernev I use npm for both frontend and backend, and I think this has become much more common. I'm also a bit concerned with loading in a giant library just for the use of a couple nice date manipulation apis. +1 for a lean-core via npm, and an easy way to optionally add locales / peripheral functionality with the default being exclusion (unless explicitly included).

One thing I think would be great to be able to do, is load a single locale as needed via webpack's ensure functionality - so you only load locale information when the user actually needs it (eg loads the page in a particular locale or switches their configured locale)

[silouanwright]

+1 definitely

[jeffbski]

+1

[seethroughdev]

would love this as well.

[dbrugne]

+1

[jhubert]

One of the first (and best) optimizations we did was remove moment.js from our client side app. I would love to use moment.js more frequently but the additional page weight just isn't worth it for the basic date manipulation we do.

So, I'm a big +1 on this as well.

[silouanwright]

@jhubert I'm actually starting to consider that. What did you replace moment with? It's one of the largest things in my app.

[jhubert]

@rey-wright I was really only using it for formatting, so I just wrote a few functions that formatted the dates exactly as I needed them and used them throughout the site. It's nothing elegant, but it's extremely fast and light.

[silouanwright]

@jhubert yeah we were doing that but... I really wish moment would be setup better...but now it's like Moment is one of the biggest pieces of our app...

So yeah we might eventually go back to this method as well. Thanks for the insight.

[gilbert]

+1. Moment.js looks great, but the 12kb makes it not worth the include (that's bigger than the framework we use!)

[DerekDomino]

tests.js file could be removed from the npm package. This file amounts to 63% of the total npm package size. A dedicated development npm package could could include this tests.js file.

For desktop applications (electron) using npm packages using moment, moment contributes significantly to the final application size (moment folder is duplicated in nested nod_modules dir).

[fresheneesz]

@DerekDomino The point of modularizing moment.js is for two reasons:

• Less code for browsers to download
• Easier to maintain many smaller packages than one large one

Removing a tests file doesn't accomplish either of those goals, and in fact doing what you suggest would make it harder to develop moment. And if you're for some reason having browsers forced to download the tests.js code, something else is going wrong.

[adalinesimonian]

@fresheneesz While yes, the suggestion doesn't fix the main problem, why would excluding a test file from the npm package make it harder to develop moment? It isn't the same as removing tests from the repository, and, generally, test code is not meant to be packaged.

[fresheneesz]

Oh, just the npm package? I guess it wouldn't then. Still don't think its a road worth traveling.

[iagopiimenta]

👍

[mmalomo]

I need this since years ago. I can not believe it is not done yet.
Im changing to moment-mini for the moment

https://github.com/ksloan/moment-mini

[ghost]

Day.Js is a nice alternative to me

⏰ Day.js 2KB immutable date library alternative to Moment.js with the same modern API

https://github.com/iamkun/dayjs

[anaibol]

https://inventi.studio/en/blog/why-you-shouldnt-use-moment-js

[nephi5]

Hi, very interested still in this feature. Any progress made?

[Carniatto]

@nephi5 @rianfowler Since this issue seems to be abandoned, you probably want to check this: https://github.com/you-dont-need/You-Dont-Need-Momentjs

[renet]

@ichernev Almost every experienced developer I talk to now recommends not using moment.js anymore. The reactions on many threads regarding this topic are pretty clear.

Can you please give us a feedback if you consider (or even already work on) a modularized moment.js package? It seems like you're ignoring this thread - please let us know, whether or not there's a chance for a modularized version. Thanks!

[stevemao]

@renet see https://github.com/you-dont-need/You-Dont-Need-Momentjs

[MickL]

With date-fns do we really need moment.js anymore?

[jeffbski-rga]

I typically recommend date-fns these days. I like the fp form myself.

[marwahaha]

See https://momentjs.com/docs/#/-project-status/

As mentioned before, the moment build without locales is of comparable size to date-fns.

[MickL]

Instead of solving something, just close the issue 👍🏻

[tomastan]

I think @marwahaha explained things pretty well in Project status section. At least it is good to know there is no reason to wait for this functionality in Moment.

[csvan]

@MickL moment.js is effectively dead, there is nothing to solve.

https://www.theregister.com/2020/09/15/moment_js_javascript_library_future/

We are migrating to https://github.com/iamkun/dayjs instead. Almost fully API-compatible with moment and extremely lightweight.

[LeoEatle]

For webpack project, use this: https://github.com/jmblog/how-to-optimize-momentjs-with-webpack

[baoanhng]

The project status page effectively explains all the thing.
https://momentjs.com/docs/#/-project-status/

You should move to other libraries if moment.js is not suitable.