JS Tutorial – Math.random() API Key Generator

Rengga Dev – Math.random() is an API in JavaScript. It is a function that gives you a random number. The number returned will be between 0 (inclusive, as in, it’s possible for an actual 0 to be returned) and 1 (exclusive, as in, it’s not possible for an actual 1 to be returned).

/**
 * Function to produce UUID.
 * See: http://stackoverflow.com/a/8809472
 */
function generateUUID()
{
    var d = new Date().getTime();
    
    if( window.performance && typeof window.performance.now === "function" )
    {
        d += performance.now();
    }
    
    var uuid = 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c)
    {
        var r = (d + Math.random()*16)%16 | 0;
        d = Math.floor(d/16);
        return (c=='x' ? r : (r&0x3|0x8)).toString(16);
    });

return uuid;
}

/**
 * Generate new key and insert into input value
 */
$( '#keygen' ).on('click',function()
{
    $( '#apikey' ).val( generateUUID() );
});

Here’s a super real-world practical use case for random numbers! The demo generates 16 random numbers to create a universally unique identifier (UUID) that can be used as a key that provides access to an API.