Js-currency-converter NPM

js-currency-converter

js-currency-converter is a currency conversion javascript module, based on Currency Converter API

Usage

npm instal js-currency-converter
Include js-currency-converter.js, or the minified version js-currency-converter.min.js in your webpage.

jQuery is the only dependency, hence it is required in order for js-currency-converter to work properly.

Instantiation

Create a new intance of CurrencyConverter:

var converter = CurrencyConverter();

If you have the paid version of the API you just have to change the API.url and add your apiKey to the API.queryParams:

var converter = CurrencyConverter({
    API : { 
        url: 'http://www.currencyconverterapi.com/api/v3/convert',
        queryParams: {
            apiKey: '987654321'
        }
    }
});

Fetch Quote

To get a fresh exchange rate from a server you can use fetchQuote function:

converter.fetchQuote('USD_EUR')
.done(function (response) {
    // response = {
    //    'USD_EUR': {
    //        val: 0.9
    //    }
    //}
})

To query multiple rates at once, with one API call, just pass in additional queries as parameters.

converter.fetchQuote('USD_EUR', 'GBP_KRW')
.done(function (response) {
    // response = {
    //    'USD_EUR': {
    //        val: 0.9
    //    },
    //    'GBP_KRW': {
    //        val: 1405.91
    //    }
    //}
})

If multiple fetchQuote function calls occur, while another fetchQuote with the same conversion rate query is in progress, multiple server calls will not be triggered. Instead, every time the same promise will be returned. Server calls are cached while in progress to converse bandwith and ease the usage.

Get Rate

To get an exchange rate for a currency you can use getRate function. If there is a cached rate available, it will be resolved, without fetching a fresh one from the server.

converter.getRate('USD_EUR')
.done(function (response) {
    // response = {
    //    'USD_EUR': {
    //        val: 0.9,
    //        expired: false
    //    }
    //}
})

To query multiple rates at once, just pass in additional queries as parameters. If there is a cached rate available, it will be resolved, without fetching a fresh one from the server.

converter.getRate('USD_EUR', 'GBP_KRW')
.done(function (response) {
    // response = {
    //    'USD_EUR': {
    //        val: 0.9,
    //        expired: false
    //    },
    //    'GBP_KRW': {
    //        val: 1405.91,
    //        expired: false
    //    }
    //}
})

If the rate is being cached from the server, and the server call fails, plugin will try to resolve an expired rate from cache. If this operation is successfull, the response will be marked with the expired flag set to true.

converter.getRate('USD_EUR')
.done(function (response) {
    // response = {
    //    'USD_EUR': {
    //        val: 0.9,
    //        expired: true
    //    }
    //}
})

Convert Amount

To convert an amount of money, you can use convertAmount function:

converter.convertAmount(100, 'USD_EUR')
.done(function (response) {
    // response = {
    //    'USD_EUR': {
    //        val: 0.9,
    //        expired: false,
    //        amount: 90
    //    }
    //}
});

To convert an amount of money, pass in additional conversion strings as parameters:

converter.convertAmount(100, 'USD_EUR', 'GBP_EUR')
.done(function (response) {
    // response = {
    //    'USD_EUR': {
    //        val: 0.9,
    //        expired: false,
    //        amount: 90
    //    },
    //    'GBP_EUR': {
    //        val: 2,
    //        expired: false
    //        amount: 200
    //    }
    // }
})

Caching

By default, CurrencyConverter caches all conversion rates to localStorage. This setting can be turned off upon instantiation:

var converter = CurrencyConverter({
    CACHE_TO_LOCAL_STORAGE : false
});

Few important rules about caching rates:

every conversion request is cached internally in the CurrencyConverter
if the CACHE_TO_LOCAL_STORAGE is set to true, internally cached rates will be cached to localStorage too (if available)
fetchQuote will always fetch rate directly from the server, bypassing any caching
getRate will always check for the internal cached rates, and if there is no valid rate (non-expired), only then the server will be queried for the new rate
when checking weather the rate is expired or not, RATES_VALIDITY_HOURS setting is used