In this article, we will explore how to extract email addresses from a string in JavaScript. Extracting email addresses from a given text can be useful for processing and organizing contact information.

There are various approaches to extract email addresses from a string in JavaScript:

Using Regular Expressions

Regular expressions provide an elegant way to match and extract email addresses from text.

Example: In this example, we will extract the substring that matches the given regular expression.

function extract(str) {
    const email = 
        /\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,}\b/g;
    return str.match(email);
}

const str = 
    "My email address is [email protected]";
console.log(extract(str));

[ '[email protected]' ]

Splitting and Filtering

In this approach we will Split the string by space using str.split() method and then use filter() method filter out valid email formats.

Example: In this example, we will use split the string and filter out the required email substring.

function extract(str) {
    const words = str.split(' ');
    const valid = words.filter(word => {
        return /\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,}\b/.test(str);
    });
    return valid;
}

const str = 
    "My email address is [email protected]";
console.log(extract(str)); 

[ 'My', 'email', 'address', 'is', '[email protected]' ]

Using String Matching and Validation

In this approach, we will check each substring for email validity.

Example: In this example we will check the email validation for every substring and display the ouput.

function isValid(str) {
    return /\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,}\b/.test(str);
}

function extract(str) {
    const words = str.split(' ');
    const email = [];
    for (const word of words) {
        if (isValid(word)) {
            email.push(word);
        }
    }
    return email;
}

const str = 
    "My email address is [email protected]";
console.log(extract(str));

[ '[email protected]' ]

Using a Custom Parser

The custom parser approach iterates through words in the text, identifying email addresses by checking for the presence of ‘@’ and ‘.’ characters, and ensuring the structure resembles an email. This method is simple and doesn’t rely on regex.

Example: The function extractEmails parses a text to find and return email addresses present within it. It searches for patterns containing ‘@’ and ‘.’, and returns them as an array.

function extractEmails(text) {
    const emails = [];
    const words = text.split(/\s+/);

    for (let word of words) {
        if (word.includes('@') && word.includes('.')) {
            const parts = word.split('@');
            if (parts.length === 2 && parts[1].includes('.')) {
                emails.push(word);
            }
        }
    }

    return emails;
}


console.log(extractEmails("Contact us at [email protected] and [email protected]")); 

[ '[email protected]', '[email protected]' ]

Using the match Method with Regular Expressions

In this approach, we use JavaScript’s match method combined with a regular expression specifically designed to capture email addresses. This method is efficient and straightforward for extracting all occurrences of email addresses from a given string.

Steps:

• Define the Regular Expression: Create a regular expression pattern that matches typical email addresses.
• Use the match Method: Apply the match method on the input string with the defined regular expression to extract all email addresses.
• Handle the Results: The result will be an array of email addresses or null if no matches are found.

Example: This example demonstrates how to extract email addresses from a string using the match method and regular expressions.

function extractEmailsUsingMatch(input) {
    // Define a regular expression for matching email addresses
    const emailRegex = /[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}/g;
    
    // Use the match method to find all email addresses in the input string
    const matches = input.match(emailRegex);
    
    // Return the array of matched email addresses or an empty array if no matches are found
    return matches || [];
}

// Example usage:
let inputString = "Contact us at [email protected], [email protected], or [email protected] for more information.";
let emailAddresses = extractEmailsUsingMatch(inputString);
console.log(emailAddresses);  // Output: ["[email protected]", "[email protected]", "[email protected]"]

[ '[email protected]', '[email protected]', '[email protected]' ]