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JavaScript

Posted by Stephen Chamroeun
Stephen Chamroeun
7,095 Points

Sharing my code

alert(`Let's do some math!`);

const num1 = prompt('Please provide a number.');
const num2 = prompt('Please provide another number.');

const input1 = parseInt(num1);
const input2 = parseInt(num2);

let message = `<h1>Math with the numbers ${num1} and ${num2}</h1><br>
                        ${input1} + ${input2} = ${input1 + input2}<br>
                        ${input1} * ${input2} = ${input1 * input2}<br>
                      ${input1} / ${input2} = ${input1 / input2}<br>
                        ${input1} - ${input2} = ${input1 - input2}<br>`;

document.write(message);

The code works. I just wanted feedback to see if the code could be refactored? Thank you!

Stephen Chamroeun
Stephen Chamroeun
7,095 Points 
alert(`Let's do some math!`);

const num1 = prompt('Please provide a number.');
const num2 = prompt('Please provide another number.');

const input1 = parseInt(num1);
const input2 = parseInt(num2);

if ( isNaN(input1) || isNaN(input2) ) {
    document.write(`<strong>Both inputs have to be of numeric value. Reload and try again.</strong>`);
} else {
    let message = 
`<h1>Math with the numbers ${num1} and ${num2}</h1><br>
    ${input1} + ${input2} = ${input1 + input2}<br>
    ${input1} * ${input2} = ${input1 * input2}<br>
    ${input1} / ${input2} = ${input1 / input2}<br>
    ${input1} - ${input2} = ${input1 - input2}<br>`;
    document.write(message);
}

I've made a few quick edits. Dave had mentioned the NaN method towards the end of the video, so I included that too. Thank you to whomever reviews my code!

2 Answers

Julia Lam (Daly)
Julia Lam (Daly)
5,230 Points
Julia Lam (Daly)
Julia Lam (Daly)
5,230 Points

Hi Stephen,

Your code looks great.
I have two suggestions:

  1. indent `<h1>Math with the numbers ${num1} and ${num2}</h1><br> .
  2. remove <br> after </h1> . Unless you need extra line break. ```
Stephen Chamroeun
Stephen Chamroeun
7,095 Points

I was in the zone and overlooked that <br> haha. Thank you for spotting that. I shall make that correction.

Steven Parker
Steven Parker
231,153 Points
Steven Parker
Steven Parker
231,153 Points

Good job! :+1:   And just for fun...

A purely optional but cute trick is to take advantage of the fact that any math done with NaN will return NaN:

if (isNaN(input1 + input2)) {

And since you have template literals, another cute trick with them for much more compact code:

    document.write(`<h1>Math with the numbers ${num1} and ${num2}</h1>`);
    for (let c of "+*/-")    // use a loop to do all 4 operations
        document.write(`${input1} ${c} ${input2} = ${eval(`input1 ${c} input2`)}<br>`);
Stephen Chamroeun
Stephen Chamroeun
7,095 Points

ahhhhh, I shall try this. Thank you for that. I really appreciate it!