curriculum/challenges/english/blocks/workshop-decimal-to-binary-converter/64007367d54d2a7efbf44fcf.md
Next, you need to check if the value returned by the parseInt() function is a number or not.
To do that, you can use the isNaN() function. This function takes in a string or number as an argument, and returns true if it evaluates to NaN. For example:
isNaN("test"); // true
isNaN(2); // false
isNaN("3.5"); // false
Update the second condition in your if statement to use the isNaN() function to check if the value returned by parseInt() is NaN.
Also, as we mentioned in step 1, we are considering only positive numbers, so we should add a third condition to the if statement to check whether the number is less than 0 (i.e., negative numbers).
6 < 0; // false
-1 < 0; // true
-8 < 0; // true
0 < 0; //false
You should wrap the value returned by parseInt() in the isNaN() function. And add a third condition which checks the value returned by parseInt() to be less than 0.
assert.match(String(checkUserInput), /if\s*\(\s*!\s*numberInput\s*\.\s*value\s*\|\|\s*isNaN\(\s*parseInt\(\s*numberInput\s*\.\s*value\s*\)\s*\)\s*\|\|\s*parseInt\(\s*numberInput\s*\.\s*value\s*\)\s*\<\s*0\s*\)\s*\{/);
The body of your if statement within checkUserInput should be empty.
assert.match(String(checkUserInput), /if\s*\(\s*.+\s*\)\s*\{\s*\}/);
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Decimal to Binary Converter</title>
<link rel="stylesheet" href="styles.css" />
</head>
<body>
<h1>
Decimal to Binary
Converter
</h1>
<section class="input-container">
<label for="number-input">Enter a decimal number:</label>
<input
value=""
type="number"
name="decimal number input"
id="number-input"
class="number-input"
/>
<button class="convert-btn" id="convert-btn">Convert</button>
</section>
<section class="output-container">
<output id="result" for="number-input"></output>
<h2>Call stack</h2>
<div id="animation-container"></div>
</section>
<script src="script.js"></script>
</body>
</html>
*,
*::before,
*::after {
box-sizing: border-box;
margin: 0;
padding: 0;
}
:root {
--light-grey: #f5f6f7;
--dark-blue: #1b1b32;
--orange: #f1be32;
}
body {
display: flex;
flex-direction: column;
align-items: center;
font-family: Menlo, Consolas, Monaco, Liberation Mono, Lucida Console,
monospace;
font-size: 1.125rem;
color: var(--light-grey);
background-color: var(--dark-blue);
padding: 0 4px;
}
h1 {
font-size: 2.125rem;
text-align: center;
margin: 20px 0;
}
h2 {
font-size: 1.5rem;
text-align: center;
margin: 20px 0;
}
.input-container {
display: flex;
flex-direction: column;
gap: 10px;
justify-content: center;
align-items: center;
width: clamp(320px, 50vw, 460px);
margin: 10px auto;
}
.input-container label {
white-space: nowrap;
word-spacing: -6px;
}
.convert-btn {
font-size: inherit;
font-family: inherit;
background-color: var(--orange);
width: 100%;
height: 2rem;
padding: 0 6px;
border: none;
border-radius: 2px;
cursor: pointer;
}
.number-input {
font-size: inherit;
padding: 0.3rem;
width: 100%;
}
.output-container {
margin-inline: auto;
width: clamp(320px, 50vw, 460px);
}
#result {
display: flex;
align-items: center;
justify-content: center;
font-size: 2rem;
text-align: center;
min-height: 80px;
margin-block-start: 20px;
padding: 15px;
border: 2px solid var(--orange);
border-radius: 2px;
}
#animation-container {
display: flex;
flex-direction: column-reverse;
justify-content: end;
gap: 1rem;
margin-block-end: 1rem;
min-height: 40vh;
border: 2px dashed var(--orange);
padding: 1rem;
}
.animation-frame {
font-family: -apple-system, BlinkMacSystemFont, avenir next, avenir, segoe ui,
helvetica neue, helvetica, Cantarell, Ubuntu, roboto, noto, arial,
sans-serif;
padding: 15px 10px;
border: 5px solid var(--orange);
font-size: 1.2rem;
text-align: center;
}
@media screen and (min-width: 36em) {
body {
font-size: 1rem;
}
.input-container {
flex-direction: row;
width: unset;
}
.number-input {
width: unset;
}
}
const numberInput = document.getElementById("number-input");
const convertBtn = document.getElementById("convert-btn");
const result = document.getElementById("result");
const checkUserInput = () => {
--fcc-editable-region--
if (!numberInput.value || parseInt(numberInput.value)) {
}
--fcc-editable-region--
console.log(numberInput.value);
};
convertBtn.addEventListener("click", checkUserInput);
numberInput.addEventListener("keydown", (e) => {
if (e.key === "Enter") {
checkUserInput();
}
});