How to create hash from string in JavaScript ?

In order to create a unique hash from a specific string, it can be implemented using its own string-to-hash converting function. It will return the hash equivalent of a string. Also, a library named Crypto can be used to generate various types of hashes like SHA1, MD5, SHA256, and many more. 

Note: The hash value of an empty string is always zero. 

Example 1: In this example, we will create a hash from a string in Javascript.

html

<center>
    <h1>GeeksforGeeks</h1>

    <h3>Creating hash from string in JavaScript?</h3>

    <p>The hash value of string "GeeksforGeeks" is .</p>

    <p id="geek"></p>

    <script>
        // Convert to 32bit integer
        function stringToHash(string) {

            var hash = 0;

            if (string.length == 0) return hash;

            for (i = 0; i < string.length; i++) {
                char = string.charCodeAt(i);
                hash = ((hash << 5) - hash) + char;
                hash = hash & hash;
            }

            return hash;
        }

        // String printing in hash
        var gfg = "GeeksforGeeks"

        document.getElementById("geek").innerHTML
                    = stringToHash(gfg);
    </script>
</center>

Output:

Example 2: In this example, we will create a hash from a string in Javascript.

javascript

<script>
    // Importing 'crypto' module
    const crypto = require('crypto'),

    // Returns the names of supported hash algorithms
    // such as SHA1,MD5
    hash = crypto.getHashes();

    // Create hash of SHA1 type
    x = "Geek"

    // 'digest' is the output of hash function containing
    // only hexadecimal digits
    hashPwd = crypto.createHash('sha1').update(x).digest('hex');

    console.log(hash);
</script>

Output: 

321cca8846c784b6f2d6ba628f8502a5fb0683ae