General

Build A Currency Converter App with JavaScript

by Bankygold7904010

This JavaScript application enables users to convert a specified amount from one currency to another. To ensure accurate conversions, the following input validation rules apply:

  • The amount field cannot be left blank.
  • A value of 0 is not permitted as an amount.

If either of these conditions is not met, the application will automatically populate the amount field with a default value of “1”, enabling users to proceed with the conversion.

Accessing the Source Code
If you’re interested in exploring the JavaScript Currency Converter’s source code, you can find the download link at the bottom of this page. Before diving into the code, let’s break down the key concepts and implementation details.

Codes and Concepts Behind the JavaScript Currency Converter


The project consists of two primary JavaScript files:

country-list.js
This file contains an object that stores country codes and their corresponding currency codes.

script.js
In this file, we:

  1. Dynamically create option tags and populate them with currency codes using a for-in loop.
  2. Insert these option tags into a select tag, enabling users to choose their desired currency.

By understanding these core concepts, you’ll be better equipped to navigate and customize the source code to suit your needs.

Processing User Input and API Requests
To facilitate currency conversion, I created a function that retrieves the user-entered amount and selected “from” and “to” currency codes.

API Request and Data Processing

  1. The function sends a GET request to an exchange rate API, passing the user-selected “from” currency code as a parameter.
  2. The API returns an object containing conversion rates for all countries relative to the user-selected “from” currency.
  3. I extract the conversion rate for the user-selected “to” currency and calculate the converted amount by multiplying it with the user-entered amount.
  4. The result is then displayed in the exchange rate text field.

Swapping Currency Codes
To enable currency code swapping, I simply reverse the “from” and “to” currency codes and recall the function.

Displaying Country Flags
To add a visual touch, I utilized the (link unavailable) API to display the user-selected country flag, enhancing the overall user experience.

Index.html File

<!DOCTYPE html>
<html lang="en" dir="ltr">
  <head>
    <meta charset="utf-8">
    <title>Currency Converter App in JavaScript</title>
    <link rel="stylesheet" href="style.css">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <!-- FontAweome CDN Link for Icons -->
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.15.3/css/all.min.css"/>
  </head>
  <body>
    <div class="wrapper">
      <header>Currency Converter</header>
      <form action="#">
        <div class="amount">
          <p>Enter Amount</p>
          <input type="text" value="1">
        </div>
        <div class="drop-list">
          <div class="from">
            <p>From</p>
            <div class="select-box">
              <img src="https://flagcdn.com/48x36/us.png" alt="flag">
              <select> <!-- Options tag are inserted from JavaScript --> </select>
            </div>
          </div>
          <div class="icon"><i class="fas fa-exchange-alt"></i></div>
          <div class="to">
            <p>To</p>
            <div class="select-box">
              <img src="https://flagcdn.com/48x36/np.png" alt="flag">
              <select> <!-- Options tag are inserted from JavaScript --> </select>
            </div>
          </div>
        </div>
        <div class="exchange-rate">Getting exchange rate...</div>
        <button>Get Exchange Rate</button>
      </form>
    </div>

    <script src="js/country-list.js"></script>
    <script src="js/script.js"></script>

  </body>
</html>

Styles.css

/* Import Google Font - Poppins */
@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@400;500;600;700&display=swap');
*{
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Poppins', sans-serif;
}
body{
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: 0 10px;
  background: #675AFE;
}
::selection{
  color: #fff;
  background: #675AFE;
}
.wrapper{
  width: 370px;
  padding: 30px;
  border-radius: 7px;
  background: #fff;
  box-shadow: 7px 7px 20px rgba(0, 0, 0, 0.05);
}
.wrapper header{
  font-size: 28px;
  font-weight: 500;
  text-align: center;
}
.wrapper form{
  margin: 40px 0 20px 0;
}
form :where(input, select, button){
  width: 100%;
  outline: none;
  border-radius: 5px;
  border: none;
}
form p{
  font-size: 18px;
  margin-bottom: 5px;
}
form input{
  height: 50px;
  font-size: 17px;
  padding: 0 15px;
  border: 1px solid #999;
}
form input:focus{
  padding: 0 14px;
  border: 2px solid #675AFE;
}
form .drop-list{
  display: flex;
  margin-top: 20px;
  align-items: center;
  justify-content: space-between;
}
.drop-list .select-box{
  display: flex;
  width: 115px;
  height: 45px;
  align-items: center;
  border-radius: 5px;
  justify-content: center;
  border: 1px solid #999;
}
.select-box img{
  max-width: 21px;
}
.select-box select{
  width: auto;
  font-size: 16px;
  background: none;
  margin: 0 -5px 0 5px;
}
.select-box select::-webkit-scrollbar{
  width: 8px;
}
.select-box select::-webkit-scrollbar-track{
  background: #fff;
}
.select-box select::-webkit-scrollbar-thumb{
  background: #888;
  border-radius: 8px;
  border-right: 2px solid #ffffff;
}
.drop-list .icon{
  cursor: pointer;
  margin-top: 30px;
  font-size: 22px;
}
form .exchange-rate{
  font-size: 17px;
  margin: 20px 0 30px;
}
form button{
  height: 52px;
  color: #fff;
  font-size: 17px;
  cursor: pointer;
  background: #675AFE;
  transition: 0.3s ease;
}
form button:hover{
  background: #4534fe;
}

Country-list.js

let country_list = {
    "AED" : "AE",
    "AFN" : "AF",
    "XCD" : "AG",
    "ALL" : "AL",
    "AMD" : "AM",
    "ANG" : "AN",
    "AOA" : "AO",
    "AQD" : "AQ",
    "ARS" : "AR",
    "AUD" : "AU",
    "AZN" : "AZ",
    "BAM" : "BA",
    "BBD" : "BB",
    "BDT" : "BD",
    "XOF" : "BE",
    "BGN" : "BG",
    "BHD" : "BH",
    "BIF" : "BI",
    "BMD" : "BM",
    "BND" : "BN",
    "BOB" : "BO",
    "BRL" : "BR",
    "BSD" : "BS",
    "NOK" : "BV",
    "BWP" : "BW",
    "BYR" : "BY",
    "BZD" : "BZ",
    "CAD" : "CA",
    "CDF" : "CD",
    "XAF" : "CF",
    "CHF" : "CH",
    "CLP" : "CL",
    "CNY" : "CN",
    "COP" : "CO",
    "CRC" : "CR",
    "CUP" : "CU",
    "CVE" : "CV",
    "CYP" : "CY",
    "CZK" : "CZ",
    "DJF" : "DJ",
    "DKK" : "DK",
    "DOP" : "DO",
    "DZD" : "DZ",
    "ECS" : "EC",
    "EEK" : "EE",
    "EGP" : "EG",
    "ETB" : "ET",
    "EUR" : "FR",
    "FJD" : "FJ",
    "FKP" : "FK",
    "GBP" : "GB",
    "GEL" : "GE",
    "GGP" : "GG",
    "GHS" : "GH",
    "GIP" : "GI",
    "GMD" : "GM",
    "GNF" : "GN",
    "GTQ" : "GT",
    "GYD" : "GY",
    "HKD" : "HK",
    "HNL" : "HN",
    "HRK" : "HR",
    "HTG" : "HT",
    "HUF" : "HU",
    "IDR" : "ID",
    "ILS" : "IL",
    "INR" : "IN",
    "IQD" : "IQ",
    "IRR" : "IR",
    "ISK" : "IS",
    "JMD" : "JM",
    "JOD" : "JO",
    "JPY" : "JP",
    "KES" : "KE",
    "KGS" : "KG",
    "KHR" : "KH",
    "KMF" : "KM",
    "KPW" : "KP",
    "KRW" : "KR",
    "KWD" : "KW",
    "KYD" : "KY",
    "KZT" : "KZ",
    "LAK" : "LA",
    "LBP" : "LB",
    "LKR" : "LK",
    "LRD" : "LR",
    "LSL" : "LS",
    "LTL" : "LT",
    "LVL" : "LV",
    "LYD" : "LY",
    "MAD" : "MA",
    "MDL" : "MD",
    "MGA" : "MG",
    "MKD" : "MK",
    "MMK" : "MM",
    "MNT" : "MN",
    "MOP" : "MO",
    "MRO" : "MR",
    "MTL" : "MT",
    "MUR" : "MU",
    "MVR" : "MV",
    "MWK" : "MW",
    "MXN" : "MX",
    "MYR" : "MY",
    "MZN" : "MZ",
    "NAD" : "NA",
    "XPF" : "NC",
    "NGN" : "NG",
    "NIO" : "NI",
    "NPR" : "NP",
    "NZD" : "NZ",
    "OMR" : "OM",
    "PAB" : "PA",
    "PEN" : "PE",
    "PGK" : "PG",
    "PHP" : "PH",
    "PKR" : "PK",
    "PLN" : "PL",
    "PYG" : "PY",
    "QAR" : "QA",
    "RON" : "RO",
    "RSD" : "RS",
    "RUB" : "RU",
    "RWF" : "RW",
    "SAR" : "SA",
    "SBD" : "SB",
    "SCR" : "SC",
    "SDG" : "SD",
    "SEK" : "SE",
    "SGD" : "SG",
    "SKK" : "SK",
    "SLL" : "SL",
    "SOS" : "SO",
    "SRD" : "SR",
    "STD" : "ST",
    "SVC" : "SV",
    "SYP" : "SY",
    "SZL" : "SZ",
    "THB" : "TH",
    "TJS" : "TJ",
    "TMT" : "TM",
    "TND" : "TN",
    "TOP" : "TO",
    "TRY" : "TR",
    "TTD" : "TT",
    "TWD" : "TW",
    "TZS" : "TZ",
    "UAH" : "UA",
    "UGX" : "UG",
    "USD" : "US",
    "UYU" : "UY",
    "UZS" : "UZ",
    "VEF" : "VE",
    "VND" : "VN",
    "VUV" : "VU",
    "YER" : "YE",
    "ZAR" : "ZA",
    "ZMK" : "ZM",
    "ZWD" : "ZW"
}

Script.js

const dropList = document.querySelectorAll("form select"),
fromCurrency = document.querySelector(".from select"),
toCurrency = document.querySelector(".to select"),
getButton = document.querySelector("form button");

for (let i = 0; i < dropList.length; i++) {
    for(let currency_code in country_list){
        let selected = i == 0 ? currency_code == "USD" ? "selected" : "" : currency_code == "NPR" ? "selected" : "";
        let optionTag = `<option value="${currency_code}" ${selected}>${currency_code}</option>`;
        dropList[i].insertAdjacentHTML("beforeend", optionTag);
    }
    dropList[i].addEventListener("change", e =>{
        loadFlag(e.target);
    });
}

function loadFlag(element){
    for(let code in country_list){
        if(code == element.value){
            let imgTag = element.parentElement.querySelector("img");
            imgTag.src = `https://flagcdn.com/48x36/${country_list[code].toLowerCase()}.png`;
        }
    }
}

window.addEventListener("load", ()=>{
    getExchangeRate();
});

getButton.addEventListener("click", e =>{
    e.preventDefault();
    getExchangeRate();
});

const exchangeIcon = document.querySelector("form .icon");
exchangeIcon.addEventListener("click", ()=>{
    let tempCode = fromCurrency.value;
    fromCurrency.value = toCurrency.value;
    toCurrency.value = tempCode;
    loadFlag(fromCurrency);
    loadFlag(toCurrency);
    getExchangeRate();
})

function getExchangeRate(){
    const amount = document.querySelector("form input");
    const exchangeRateTxt = document.querySelector("form .exchange-rate");
    let amountVal = amount.value;
    if(amountVal == "" || amountVal == "0"){
        amount.value = "1";
        amountVal = 1;
    }
    exchangeRateTxt.innerText = "Getting exchange rate...";
    let url = `https://v6.exchangerate-api.com/v6/YOUR-API-KEY/latest/${fromCurrency.value}`;
    fetch(url).then(response => response.json()).then(result =>{
        let exchangeRate = result.conversion_rates[toCurrency.value];
        let totalExRate = (amountVal * exchangeRate).toFixed(2);
        exchangeRateTxt.innerText = `${amountVal} ${fromCurrency.value} = ${totalExRate} ${toCurrency.value}`;
    }).catch(() =>{
        exchangeRateTxt.innerText = "Something went wrong";
    });
}

Related posts

Complete Budget Tracker Frontend Source Code

Bankygold7904

Build A Google Gemini Chatbot with HTML CSS and JavaScript

Bankygold7904

Responsive Login form in React Js and CSS

Bankygold7904

Leave a Comment

Save my name, email, and website in this browser for the next time I comment.