Generate Random Hex String in NodeJS

rand_string.node.js

function rand_string(n) {
    if (n <= 0) {
        return '';
    }
    var rs = '';
    try {
        rs = crypto.randomBytes(Math.ceil(n/2)).toString('hex').slice(0,n);
        /* note: could do this non-blocking, but still might fail */
    }
    catch(ex) {
        /* known exception cause: depletion of entropy info for randomBytes */
        console.error('Exception generating random string: ' + ex);
        /* weaker random fallback */
        rs = '';
        var r = n % 8, q = (n-r)/8, i;
        for(i = 0; i < q; i++) {
            rs += Math.random().toString(16).slice(2);
        }
        if(r > 0){
            rs += Math.random().toString(16).slice(2,i);
        }
    }
    return rs;
}