java script loop - how to save index values

Planning to create a program that extracts the domain from an email address. How can this be done without using built-in functions like .map .filter .reduce .split .join .indexOf .findIndex .substring? Many online sources suggest using a for loop to locate "@" and "." symbols, but how do you extract the string between these two markers as the output?

For example: Input = [email protected] Output = gmail

 Input = <a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="80f4f2e9f0ece5b2c0f9e1e8efefaee3efed">[email protected]</a>
 Output = yahoo


let input = "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="e5889c87809691a58288848c89cb868a88">[email protected]</a>"
let output = ""
let begin = ""
let end = ""

for (let i = 12; i<input.length; i++){
    if(input[i] == "@"){
        begin += input[i+1]
    }
}

for (let j = 0; j<input.length; j++){
    if(input[j] == "."){
        end += input[j-1]
    }
}

javascriptfor-loop

Answer №1

function extractEmail() {

let input = "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="aac7d3c8cfd9deeacdc7cbc3c684c9c5c7">[email protected]</a>"
let output = []
let didReachAtSymbol = false

for (let i = 0; i < input.length; i++) {
    if(input[i] == "@") {
       didReachAtSymbol = true
    } else if(input[i] == '.'){
       break
    } else if(didReachAtSymbol) {
       output.push(input[i])
    }
}

return output.join('')
}

console.log(extractEmail())

The main idea revolves around starting to add characters to the output once an @ symbol is encountered, and then stopping when a . is found. Upon encountering a ., the function breaks and returns the extracted value.

Answer №2

const email = "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="35692c282e383b0f2c262a2227612c232f">[email protected]</a>"

let startIdx = null
let endIdx = null

for (let i = 0; i < email.length; i++) {
    if (email[i] === '@') {
        startIdx = i + 1
    } else if (email[i] === '.') {
        endIdx = i + 1
        break
    }
}

let domain = email.substring(startIdx, endIdx)

This code provides a basic solution for extracting the domain from an email address, though it may not handle all potential errors smoothly.

Answer №3

It seems like you've dabbled in JavaScript which is a great start! Enhance your learning experience with code snippets like the following:

var input = "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="bacec8d3cad6df88fac3dbd2d5d594d9d5d7">[email protected]</a>"
var domainWithoutCom = input.split('@')[1].split('.')[0]
console.log(domainWithoutCom)

split function comes in handy for tasks like this!

EDIT:

I apologize for any confusion. Here's an alternate version for you to review my solution :)

Take a look at this improved snippet, it may give you some valuable insights :)

var email = '<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="2645474a504f48084853484355665f474e49490845494b">[email protected]</a>';
var count = 0;
var domain = '';
var findFirst = false;
var searching = true;
do {
    var char = email[count];
    if (findFirst) {
        if (char == '.') {
            searching = false;
        } else {
            domain += char;
        }
    }
    else {
        if (char == '@') {
            findFirst = true;
        }
    }
    count += 1;
} while (searching == true);

console.log(domain)

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