Rates(Iran's exchange rates CLI)

This CLI is built based on Scalajs. It meant to be used as educational material for scala developers who want to start with Scalajs. I use this CLI on daily bases to check the exchanges' rates from the console so I thought it might be useful for other developers as well! It is published as an NPM package as well and you can install and use it easily. If you are a Scala developer that checks the exchange rates frequently :D, feel free to make a PR to improve the CLI!

How to install

npm install -g iranrates

How to use

Usage: rates [--exchange <name>] [--symbol <name>]... [--output <output type>] [--timeout <miliseconds>]

Check the iran currency exchange rates

Options and flags:
    --help
        Display this help text.
    --version, -v
        Print the version number and exit.
    --exchange <name>, -e <name>
        The exchange to extract the rate. For example, [Bonbast,Tgju,All]
    --symbol <name>, -s <name>
        The symbol you look for its rate. For example, [All,EUR,USD,GBP,CHF,CAD,AUD,SEK,NOK,RUB,DKK,TRY,AZADI,AZADIHALF,AZADIQUARTER,AZADIGRAM,SEKEH,GGRAM,GMISQAL,GOUNCE,GOLD]
    --output <output type>, -o <output type>
        Defines the type of output For example, [h, v, horizontal, vertical]. Default is Vertical
    --timeout <miliseconds>, -t <miliseconds>
        Defines the timeout for getting the information from each exchange. Default is 3000ms.   

For example;

iranrates -e bonbast -c eur -s usd

produce something like this;

             bonbast.com             
EUR           49,500                 
USD           46,550           

or

iranrates -e all -s all

produce something like this;

                      bonbast.com          tgju.org             
AUD                   33,250               32,220               
AZADI                 28,200,000           28,201,000           
AZADIGRAM             6,800,000            6,800,000            
AZADIHALF             18,500,000           18,500,000           
AZADIQUARTER          11,200,000           11,200,000           
CAD                   36,150               35,050               
CHF                   53,950               51,940               
DKK                   7,220                6,890                
EUR                   53,800               51,133               
GBP                   60,850               58,598               
GGRAM                 2,640,702            2,640,600            
GMISQAL               11,439,000           11,436,000           
GOUNCE                197,747              19,312               
NOK                   4,775                4,500                
RUB                   650                  633                  
SEK                   4,810                4,580                
TRY                   2,595                2,530                
USD                   49,400               47,208             

New Changes

from version 0.1.0 we have changed the currency to symbol because we have added a few new rates like gold and sekeh. These are not a currency so we couldn't use the concept of currency anymore. So instead of --currency or -c you need to use --symbol or -s. A few new symbols:

• SEKEH: which includes a few other symbols(AZADI, AZADIHALF, AZADIQUARTER and AZADIGRAM).
• GOLD: which includes a few other symbols(GGRAM, GMISQAL, GOUNCE). So if you use -s SEKEH or s GOLD it will provide all the symbols under the category of SEKEH or GOLD. You can use the sub-category symbols alone as well. For example, you can request only AZADI or GGRAM,...

Why Scalajs

It might sound weird to use Scalajs to develop a CLI! Scalajs compiles to javascript and the final output of a Scalajs project is a js file that can be used in a web application that targets the browsers or in an application that targets the Nodejs platform. So we can use Nodejs as a platform for our CLI.

How to Start with Scalajs

To start with Scalajs for sure you need to know some Scala and a little bit of Javascript/Typescript and general understanding of the concept behind Nodejs. If you are targeting the browser you need to know some basics of Javascript or at least be able to read a piece of Javascript code. In general if you are targeting the Nodejs platform you need to know what is Nodejs and how it works. I think just reading this introduction would be enough!

Scalajs

You can start a Scalajs project simply like any other Scala-Sbt project by defining your build.sbt. Check out the build.sbt from this project.

• The sbt plugin sbt-scalajs helps you to develop Scalajs and finally compile your Scalajs to Javascript.
• If you want to publish your projec as a NPM package you could use this plugin sbt-npm-package

Normally when you develop an application you would need some other capabilities on top of what Scala core provides you. A few of the main scala libraries already have been published for Scalajs which means you can use them directly in your Scalajs project. For example, Cats, Cats-Effect, ZIO, FS2, ... are already been published for Scalajs as well. On top of these, you still might miss some functionalities in the Scala ecosystem. To cover those parts you could use the libraries that have already been developed in the Javascript ecosystem.

To use a javascript library in general you would need to introduce it to your project. There are a few ways to do that. In this project, we used the first one:

• Using the sbt-scalajs-bundler pluging.
• Using the sbt-jsdependencies pluging.

It is not enough to just introduce your javascript library to your project. You need to write a facade on top of the Javascript library. This is the place the having some basic knowledge of Javascript could help. You can read all about this on the Scalajs website. For example, in this project, we wrote two facades one for prompts and one for puppteer. Writing facades for big libraries could be hard and time-consuming, therefor we normally reduce the scope of the facade to the parts of the library that we use in the project. The other option would be to use ScalablyTyped which automatically converts the NPM packages to Scalajs for you. It has its own pros and cons. I used it a few times and it works at least you can use it to have an idea of how to write your minimal facade by getting some inspiration from its output!

How to run?

Like any other scala project you can use sbt to run your scalajs application. So you can use sbt run to run your application.In this project I had issue with sbt run. The cli prompts didn't work with sbt shell and I couldn't fix it! So I had to use nodejs directly to run my app.

How to run on local Nodejs?

You can use the commands below to make an npm package and install it locally: This makes a NPM package in the project target folder. After this command you can go to the folder and just use node . to run the application.

npmPackage

This will install the npm package locally so you can run it directly. In this case you can just use rates to run the nodejs application.

If you want to publish it as a NPM package you first need to create an account. Then you need to login and then use sbt command to publish it.

npm login
sbt npmPackagePublish