index.js
function(str){
    if(_.isUndefined(str))
        str = '00';
    
    return String(str).length % 2 ? '0' + String(str) : String(str);
}
function(str){
    if(_.isUndefined(str))
        str = '00';
    
    return String(str).length % 2 ? '0' + String(str) : String(str);
}
function ( str ) { if ( _ . isUndefined ( str ) ) str = '00' ; return String ( str ) . length % 2 ? '0' + String ( str ) : String ( str ) ; }
Pad the given string with a prefix zero, if length is uneven.

@method (formatHex)
@param {String} str    The string to pad for use as hex
@return {String} The padded or formatted string for use as a hex string
Pad the given string with a prefix zero if length is uneven .