Develop Reference

Angular app and internationalization and localization

we have an existing silverlight app which runs in browser + on hardware.
we want to rewrite this app using angular js and html5.
one of the key requirements with new system is support of internationalization and localization. and target countries are usa, brazil, italy for now.
Am new to this area and have lot of basic questions.
does existing database needs to be redesigned to support same ? i mean to identify columns (product_name/customer_name etc) that needs to have locale specific data and then store data for each locale and modify sprocs and webapi to accept language parameter and then get content based on that. ?
I believe we need to user nvarchar for such columns.
what will happen to currency and date time columns in db ? say there is quantity column then what should be data type of this column in db ? if current locale is Portuguese then will qty stored in Portuguese number.
what is the best practices for storing and retrieving currency column
based on locale.
what is the best practices for storing and retrieving date column
based on locale.
how to handle string checks, numeric checks in webapi methods ?
how to do comparison and checks in javascript for string,number,datetime
please share link to some good pointers which could help.
so in short right from javascript to .net webapi to database (sql) how should we take care of locale dependent logic and fields
thanks.

A lot of questions, let's see if I can answer those.
If your existing application is properly internationalized, I don't think there is any need to modify the database. Just make sure it is able to handle international characters (NCHAR, NVARCHAR, NTEXT in MS SQL, valid character encodings in others).
As for DB design, it is good to keep things locale-independent as long as you can. For instance it is better to store keys in the database and resolve them at runtime. However, if your data is dynamic (i.e. you have product names and their descriptions that changes often), the only way to go is to have translation table and look the data up using valid locale. It's quite complex in relational world (i.e. joins), but it could be done.
2,3. All the numeric columns should be kept locale-independent and formatted on the UI side. The more problematic would be prices and sales orders - you would need an additional column to store the currency code (i.e. 12.34 | USD). On the UI side you would need to pass the code to the Angular currency filter. The only gotcha here is, Angular does not support easy locale context switching, so you would need to use a hacky library like Angular Dynamic Locale to load the formats for you.
Similar. Keep it locale-independent. DB built-in types should automatically handle that for you and give you nice DateTime/DateTimeOffset (in a .Net world) back. The only gotcha would be the time zone - it may make sense to use DATETIMEOFFSET MS SQL type, as others does not store time zone.
There is an alternative way to store date and times in the database - you may decide to store it as a number of milliseconds since January 1, 1970 UTC - as BIGINT type. Especially if you are going to read this directly to JS, you will be able to easily re-create JS Date object (should you need this for calculations or something) in a valid time zone (it works the other way round as well). All you have to do to format date is to use this number (not date, that is AFAIR) and Angular's date filter with UTC as a parameter.
I don't think I understand what you're asking exactly. I guess the question is about validation of user input, rather than API. Well, beware of using Regular Expressions, because JavaScript doesn't handle Unicode well (at least in this area). You'd need to ask more precise question.
Assuming that you have Number and Date objects (i.e. typeof o == 'number') it is straightforward (as in obj1 === obj2).
As far as strings are concerned... Well, str1 === str2 will give you valid answer if you want to be exact. If you want to sort them, modern web browsers (Chrome 14+, Firefox 29+, IE11+) implement EcmaScript 402 Internationalization API so you can do something like str1.localeCompare(str2, locale), see this article.
The real problem occurs when you want to compare two strings case insensitive and accent insensitive for equality (as oppose for ordering like in case of sorting). Basically, there is no way (and this is true even in "big" programming languages like Java or C#).

Javascript: data format, akin to Spring Property Editors

Is there any library already available for javascript data format / transformation?
Example: Date, Time, Numbers, etc., can be converted to text with predefined formats.
These formats are chiefly locale based. But some how the mechanism to convert value (data, date, time..) should be there, that accepts custom format too to translate into desired formatted text.
On the contrary, the same library should be capable of parsing the text to value, with the source format knowledge.
Some thing similar to Spring's Property Editors or Converter.
Quick Searches; http://numeraljs.com/ http://www.datejs.com/
I should have mentioned the fact that, I am using DOJO as our JS Widget Library and with it comes methods and classes to address formatting / parsing, bundled.
Now that we have DOJO in place, I will be putting the code in the abstract layer (wrapper) over the library to keep the solution Library-Agnostic.
Find the code below - for brevity only the snippet is mentioned, could have done JSFiddle (may be in a day or two).
// get the DOJO handle, either from global "dojo" variable or via AMD
// var dojo = require('dojo');
............
// for date
dojo.date.locale.format(new Date(), {selector: "date",datePattern:"dd/mm/yyyy"});
// output: 31/06/2013
// for number
dojo.number.format(9999999.99,{type: "decimal",pattern:"#,##,####.##"});
// output: 9,99,9999.99
............
NOTE: An important feature it addresses is that it understands locale and can do the formatting automatically w.r.t the locale configured. DOJO library staunchly follows Java style of data formatting. If you are a Java Geek, you would find the library and format semantics easy to follow.
Find the DOJO link in this respect ://dojotoolkit.org/reference-guide/1.7/quickstart/numbersDates.html (could not post the complete link as I do not have enough reputations, please prefix "http" to the link)
Still, I would like to welcome better solution if any, for the given context.
As part of libraries used, we are using jQuery, Underscore, Backbone and DOJO primarily , all across for specific purposes in the application.

I use Moment.js for all my JS date formatting and manipulations. http://momentjs.com/

Parsing a string into a custom object based on different criteria

As part of a small project I'm working on, I need to be able to parse a string into a custom object, which represents an action, date and a few other properties. The tricky part is that the input string can come in a variety of flavors that all need to be properly parsed.
Input strings may be in the following formats:
Go to work tomorrow at 9am
Wash my car on Monday, at 3 pm
Call the doctor next Tuesday at 10am
Fill out the rebate form in 3 days at 2:30pm
Wake me up every day at 7:00am
And the output object would look something like this:
{
"Action":"Wash my car",
"DateTime":"2011-12-26 3:00PM", // Format is irrelevant at this point
"Recurring":False,
"RecurranceType":""
}
At first I thought of constructing some sort of tree to represent different states (On, In, Every, etc.) with different outcomes and further states (candidate for a state machine, right?). However, the more I thought about this, the more it started looking like a grammar parsing problem. Due to a (limited) number of ways the sentence could be formed, it looks like some sort of grammar parsing algorithm would need to be implemented.
In addition, I'm doing this on the front end, so JavaScript is the language of choice here. Back end will be written in Python and could be used by calling AJAX methods, if necessary, but I'd prefer to keep it all in JavaScript. (To be honest, I don't think the language is a big issue here).
So, am I in way over my head? I have a strong JavaScript background, but nothing beyond school courses when it comes to language design, parsing, etc. Is there a better way to solve this problem? Any suggestions are greatly appreciated.

I don't know a lot about grammar parsing, but something here might help.
My first thought is that your sentence syntax seems to be pretty consistent
1st 3-4 words are generally VERB text NOUN, followed by some form of time. If the total options are limited to what form the sentence can take, you can hard-code some parsing rules.
I also ran across a couple of js grammar parsers that might get you somewhere:
http://jscc.jmksf.com/
http://pegjs.majda.cz/
http://www.corion.net/perl-dev/Javascript-Grammar.html
This is an interesting problem you have. Please update this with your solutions later.

Localization and Time Format

We know that different locales use different date and number formats, but what about time formats? There are certainly fewer ways to format time values than date values.
I have a field in a web application that accepts a time value as free text, hour and minute only. Suppose that the field allows only one of the following formats for all locales.
23:59
2359
12:59p
p12:59
Note that "p" and ":" are customizable for each locale.
Would this be too much restriction for a localizable application supporting non-English locales? I'm asking since there's no built-in parser for time values in JavaScript and it seems that most projects build their own mini parser.

Maybe what you are looking for is JQuery Time Picker. I don't think any of these plugins support JQuery Regional scripts, but at least it should be easier to create your own localized settings instead building a parser...
If you still want to build a parser, go for it although trying to support all possible combination (like "6:40", "06:40", "6:40 P.M.") would be at least problematic. As Stefan mentioned, it is easier to do just some kind of drop-down boxes (personally I hate them as they require clicking). Otherwise you may create to text fields: one for hour part and the second one for minutes and add drop-down for selecting AM/PM conditionally (that is if preferred format for this locale is 12 hours).
What about time zones? I'd recommend that the user time zone would be in use, but the time would be then converted to UTC and stored as such internally...

Localize dates on a browser?

Let's say I have a date that I can represent in a culture-invariant format (ISO 8601).
I'll pick July 6, 2009, 3:54 pm UTC time in Paris, a.k.a. 5:54 pm local time in Paris observing daylight savings.
2009-07-06T15:54:12.000+02:00
OK... is there any hidden gem of markup that will tell the browser to convert that string into a localized version of it?
The closest solution is using Javascript's Date.prototype.toLocaleString(). It certainly does a good job, but it can be slow to iterate over a lot of dates, and it relies on Javascript.
Is there any HTML, CSS, XSLT, or otherwise semantic markup that a browser will recognize and automatically render the correct localized string?
Edit:
The method I am currently using is replacing the text of an HTML element with a localized string:
Starting with:
<span class="date">2009/07/06 15:54:12 GMT</span>
Using Javascript (with jQuery):
var dates = $("span.date", context);
// use for loop instead of .each() for speed
for(var i=0,len=dates.length; i < len; i++) {
// parse the date
var d = new Date(dates.eq(i).text());
// set the text to the localized string
dates.eq(i).text(d.toLocaleString());
}
From a practical point of view, it makes the text "flash" to the new value when the Javascript runs, and I don't like it.
From a principles point of view, I don't get why we need to do this - the browser should be able to localize standard things like currency, dates, numbers, as long as we mark it up as such.
A follow up question: Why do browsers/the Web not have such a simple feature - take a standard data item, and format it according to the client's settings?

I use toLocaleString() on my site, and I've never had a problem with the speed of it. How are you getting the server date into the Date object? Parsing?
I add a comment node right before I display the date as the server sees it. Inside the comment node is the date/time of that post as the number of milliseconds since epoch. In Rails, for example:
<!--<%= post.created_at.to_i * 1000 %>-->
If they have JS enabled, I use jQuery to grab those nodes, get the value of the comment, then:
var date = new Date();
date.setTime(msFromEpoch);
// output date.toLocaleString()
If they don't have JS enabled, they can feel free to do the conversion in their head.
If you're trying to parse the ISO time, that may be the cause of your slowness. Also, how many dates are we talking?

Unfortunately, there is not.
HTML & CSS are strictly used for presentation, as such, there is no "smarts" built in to change the way things are displayed.
Your best bet would be to use a server side language (like .NET, Python, etc.) to emit the dates into the HTML in the format you want them shown to your user.

It is not possible to do this with HTML, it has no smart tags that can make any kind of decisions like this. It is strictly presentational. I do wonder, though, if HTML5 perhaps has a tag for something like this...
Anyways, the way I see it, you have 3 options:
Stick to the Javascript way. There's questions with more details on it on this website, such as How do I display a date/time in the user’s locale format and time offset? and How can I determine a web user’s time zone?
Try to use geolocation. That is, your server side script fires off a request to one of the many geolocator services out there on the user's first page visit to try and guess where the user is. The downside of this is that it will be wrong about 10% of the time, so it's not that much better than the market share Javascript is going to get you.... (all in all, then, not a very good method...)
Ask the user! You will see that most websites that want to display a tailored experience for you will ask you this sort of thing because it's just not possible to know. As a neat fallback, you could wrap the question around <noscript> tags so you only ask those with Javascript disabled while offering the Javascript experience to those that have it.

Dojo has some pretty good localizations for dates and currencies. Using this method also allows you to pick different formats (e.g.: short date vs long date) and force locales.

The language and the user's locale should be sent on the HTTP header. You can use those to create the correct date format server-side to be displayed to the user. However, this is often undesirable because many users completely ignore their locale settings in their OS and/or browser. So, you may be feeding USA style timestamps to New Zealanders.
I liked the trick posted in the comment above, but it sounds like a QA headache, since you could be dealing with a large number of clients that implement timestamps in very different ways.
The most effective solution I have seen, is to simple provide a panel to allow your users to choose what time format they like. Some users even ****gasp**** like ISO formats. Then you do the time format conversion server side. If your application language does not have good locale to timezone formatting mapping, check your database. Many databases provide locale-based customized timezone formatting as well.

Because this anwser still popups in google I share that this is now possible to do by using a readonly datetime-local input (see below) and you can then style the input the way you want:
<input type="datetime-local" value="2018-06-12T19:30" readonly />
For more information see: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/input/datetime-local