abcdefghiJS · leehyewon0531 · Apr 1, 2022 · chaeiJeon · Apr 3, 2022 · chaeiJeon
diff --git a/hyewon/4-exchangeRate/README.md b/hyewon/4-exchangeRate/README.md
@@ -0,0 +1,58 @@
+# 목차
+- `fetch()`
+- swap
+
+## `fetch()`
+- - -
+- Fetch API 를 이용하면 Request/Response 를 조작하는 것이 가능하다.
+- fetch() 메소드는 첫번째 인자로 URL, 두번째 인자로 option 객체를 받고, Promise 객체를 반환한다. <br />
+반환된 객체는 API 호출이 성공했을 경우에는 response 객체를 resolve 하고, 실패했을 경우에는 error 객체를 reject 한다.
+
+### 내 코드
+```javascript
+fetch("https://v6.exchangerate-api.com/v6/0c8fbd2c3ca43caf99612cff/latest/USD")
+    .then((response) => { return response.json() })
+    .then((response) => {
+        // 생략
+    })
+```
+그런데 왜 첫번째 then() 에서 바로 response.json() 을 사용하지 않고 그 다음 then() 으로 넘겨줘야만 하는지 잘 모르겠다... 
+
+## swap
+- - -
+```javascript
+//JavaScript program to swap two variables
+
+//take input from the users
+let a = prompt('Enter the first variable: ');
+let b = prompt('Enter the second variable: ');
+
+//using destructuring assignment
+[a, b] = [b, a];
+
+console.log(`The value of a after swapping: ${a}`);
+console.log(`The value of b after swapping: ${b}`);
+```
+↑ 구조 분해 할당을 이용한 변수 값 교환
+
+### 내 코드
+```javascript
+function swap() {
+    const firIndex = $firstSelect.selectedIndex
+    const secIndex = $secondSelect.selectedIndex
+    $firstSelect.options[secIndex].selected = true
+    $secondSelect.options[firIndex].selected = true
+    [$firstSelect, $secondSelect] = [$secondSelect, $firstSelect]
+    calculate()
+}
+```
+
+## 참조
+- - -
+- `fetch()` <br />
+https://developer.mozilla.org/ko/docs/Web/API/Fetch_API/Using_Fetch <br />
+https://developer.mozilla.org/en-US/docs/Web/API/fetch <br />
+https://www.daleseo.com/js-window-fetch/ <br />
+- swap <br />
+https://www.programiz.com/javascript/examples/swap-variables <br />
+https://developer.mozilla.org/ko/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment <br />
diff --git a/hyewon/4-exchangeRate/img/money.png b/hyewon/4-exchangeRate/img/money.png
diff --git a/hyewon/4-exchangeRate/index.html b/hyewon/4-exchangeRate/index.html
@@ -0,0 +1,142 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <meta http-equiv="X-UA-Compatible" content="ie=edge" />
+    <title>Exchange Rate Calculator</title>
+    <link rel="stylesheet" href="style.css" />
+  </head>
+  <body>
+    <img src="img/money.png" alt="" class="money-img" />
+    <h1>Exchange Rate Calculator</h1>
+    <p>Choose the currency and the amounts to get the exchange rate</p>
+
+    <div class="container">
+      <div class="currency">
+        <select id="currency-one" onchange="calculate()">
+          <option value="AED">AED</option>
+          <option value="ARS">ARS</option>
+          <option value="AUD">AUD</option>
+          <option value="BGN">BGN</option>
+          <option value="BRL">BRL</option>
+          <option value="BSD">BSD</option>
+          <option value="CAD">CAD</option>
+          <option value="CHF">CHF</option>
+          <option value="CLP">CLP</option>
+          <option value="CNY">CNY</option>
+          <option value="COP">COP</option>
+          <option value="CZK">CZK</option>
+          <option value="DKK">DKK</option>
+          <option value="DOP">DOP</option>
+          <option value="EGP">EGP</option>
+          <option value="EUR">EUR</option>
+          <option value="FJD">FJD</option>
+          <option value="GBP">GBP</option>
+          <option value="GTQ">GTQ</option>
+          <option value="HKD">HKD</option>
+          <option value="HRK">HRK</option>
+          <option value="HUF">HUF</option>
+          <option value="IDR">IDR</option>
+          <option value="ILS">ILS</option>
+          <option value="INR">INR</option>
+          <option value="ISK">ISK</option>
+          <option value="JPY">JPY</option>
+          <option value="KRW">KRW</option>
+          <option value="KZT">KZT</option>
+          <option value="MXN">MXN</option>
+          <option value="MYR">MYR</option>
+          <option value="NOK">NOK</option>
+          <option value="NZD">NZD</option>
+          <option value="PAB">PAB</option>
+          <option value="PEN">PEN</option>
+          <option value="PHP">PHP</option>
+          <option value="PKR">PKR</option>
+          <option value="PLN">PLN</option>
+          <option value="PYG">PYG</option>
+          <option value="RON">RON</option>
+          <option value="RUB">RUB</option>
+          <option value="SAR">SAR</option>
+          <option value="SEK">SEK</option>
+          <option value="SGD">SGD</option>
+          <option value="THB">THB</option>
+          <option value="TRY">TRY</option>
+          <option value="TWD">TWD</option>
+          <option value="UAH">UAH</option>
+          <option value="USD" selected>USD</option>
+          <option value="UYU">UYU</option>
+          <option value="VND">VND</option>
+          <option value="ZAR">ZAR</option>
+        </select>
+        <input type="number" id="amount-one" placeholder="0" value="1" onchange="calculate()"/>
+      </div>
+
+      <div class="swap-rate-container">
+        <button class="btn" id="swap" onclick="swap()">
+          Swap
+        </button>
+        <div class="rate" id="rate"></div>
+      </div>
+
+      <div class="currency">
+        <select id="currency-two" onchange="calculate()">
+          <option value="AED">AED</option>
+          <option value="ARS">ARS</option>
+          <option value="AUD">AUD</option>
+          <option value="BGN">BGN</option>
+          <option value="BRL">BRL</option>
+          <option value="BSD">BSD</option>
+          <option value="CAD">CAD</option>
+          <option value="CHF">CHF</option>
+          <option value="CLP">CLP</option>
+          <option value="CNY">CNY</option>
+          <option value="COP">COP</option>
+          <option value="CZK">CZK</option>
+          <option value="DKK">DKK</option>
+          <option value="DOP">DOP</option>
+          <option value="EGP">EGP</option>
+          <option value="EUR" selected>EUR</option>
+          <option value="FJD">FJD</option>
+          <option value="GBP">GBP</option>
+          <option value="GTQ">GTQ</option>
+          <option value="HKD">HKD</option>
+          <option value="HRK">HRK</option>
+          <option value="HUF">HUF</option>
+          <option value="IDR">IDR</option>
+          <option value="ILS">ILS</option>
+          <option value="INR">INR</option>
+          <option value="ISK">ISK</option>
+          <option value="JPY">JPY</option>
+          <option value="KRW">KRW</option>
+          <option value="KZT">KZT</option>
+          <option value="MXN">MXN</option>
+          <option value="MYR">MYR</option>
+          <option value="NOK">NOK</option>
+          <option value="NZD">NZD</option>
+          <option value="PAB">PAB</option>
+          <option value="PEN">PEN</option>
+          <option value="PHP">PHP</option>
+          <option value="PKR">PKR</option>
+          <option value="PLN">PLN</option>
+          <option value="PYG">PYG</option>
+          <option value="RON">RON</option>
+          <option value="RUB">RUB</option>
+          <option value="SAR">SAR</option>
+          <option value="SEK">SEK</option>
+          <option value="SGD">SGD</option>
+          <option value="THB">THB</option>
+          <option value="TRY">TRY</option>
+          <option value="TWD">TWD</option>
+          <option value="UAH">UAH</option>
+          <option value="USD">USD</option>
+          <option value="UYU">UYU</option>
+          <option value="VND">VND</option>
+          <option value="ZAR">ZAR</option>
+        </select>
+        <input type="number" id="amount-two" placeholder="0" />
+      </div>
+    </div>
+
+    <script src="script.js"></script>
+  </body>
+</html>
diff --git a/hyewon/4-exchangeRate/script.js b/hyewon/4-exchangeRate/script.js
@@ -0,0 +1,29 @@
+const $firstSelect = document.getElementById('currency-one')
+const $secondSelect = document.getElementById('currency-two')
+const $rate = document.getElementById('rate')
+const $amount1 = document.getElementById('amount-one')
+const $amount2 = document.getElementById('amount-two')
+
+calculate()
+
+function calculate() {
+    const firstCountry = $firstSelect.options[$firstSelect.selectedIndex].value
+    const secondCountry = $secondSelect.options[$secondSelect.selectedIndex].value
+
+    fetch("https://v6.exchangerate-api.com/v6/0c8fbd2c3ca43caf99612cff/latest/USD")
+        .then((response) => { return response.json() })
+        .then((response) => {
+            const rate = ((response.conversion_rates[secondCountry]) / (response.conversion_rates[firstCountry])).toFixed(3)
+            $rate.textContent = `1 ${firstCountry} = ${rate} ${secondCountry}`
+            $amount2.value = (parseFloat($amount1.value) * rate).toFixed(2)
+        })
+}
+
+function swap() {
+    const firIndex = $firstSelect.selectedIndex
+    const secIndex = $secondSelect.selectedIndex
+    $firstSelect.options[secIndex].selected = true
+    $secondSelect.options[firIndex].selected = true
+    [$firstSelect, $secondSelect] = [$secondSelect, $firstSelect]
+    calculate()
+}
diff --git a/hyewon/4-exchangeRate/style.css b/hyewon/4-exchangeRate/style.css
@@ -0,0 +1,93 @@
+:root {
+    --primary-color: #5fbaa7;
+  }
+
+  * {
+    box-sizing: border-box;
+  }
+
+  body {
+    background-color: #f4f4f4;
+    font-family: Arial, Helvetica, sans-serif;
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    justify-content: center;
+    height: 100vh;
+    margin: 0;
+    padding: 20px;
+  }
+
+  h1 {
+    color: var(--primary-color);
+  }
+
+  p {
+    text-align: center;
+  }
+
+  .btn {
+    color: #fff;
+    background: var(--primary-color);
+    cursor: pointer;
+    border-radius: 5px;
+    font-size: 12px;
+    padding: 5px 12px;
+  }
+
+  .money-img {
+    width: 150px;
+  }
+
+  .currency {
+    padding: 40px 0;
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+  }
+
+  .currency select {
+    padding: 10px 20px 10px 10px;
+    -moz-appearance: none;
+    -webkit-appearance: none;
+    appearance: none;
+    border: 1px solid #dedede;
+    font-size: 16px;
+    /*  You may not need these following lines. The arrow did not show for me on MacOS/Chrome so I added it. Just remove it if you would like  */
+    background: transparent;
+    background-image: url('data:image/svg+xml;charset=US-ASCII,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20width%3D%22292.4%22%20height%3D%22292.4%22%3E%3Cpath%20fill%3D%22%20000002%22%20d%3D%22M287%2069.4a17.6%2017.6%200%200%200-13-5.4H18.4c-5%200-9.3%201.8-12.9%205.4A17.6%2017.6%200%200%200%200%2082.2c0%205%201.8%209.3%205.4%2012.9l128%20127.9c3.6%203.6%207.8%205.4%2012.8%205.4s9.2-1.8%2012.8-5.4L287%2095c3.5-3.5%205.4-7.8%205.4-12.8%200-5-1.9-9.2-5.5-12.8z%22%2F%3E%3C%2Fsvg%3E');
+    background-position: right 10px top 50%, 0, 0;
+    background-size: 12px auto, 100%;
+    background-repeat: no-repeat;
+  }
+
+  .currency input {
+    border: 0;
+    background: transparent;
+    font-size: 30px;
+    text-align: right;
+  }
+
+  .swap-rate-container {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+  }
+
+  .rate {
+    color: var(--primary-color);
+    font-size: 14px;
+    padding: 0 10px;
+  }
+
+  select:focus,
+  input:focus,
+  button:focus {
+    outline: 0;
+  }
+
+  @media (max-width: 600px) {
+    .currency input {
+      width: 200px;
+    }
+  }