ExtJS 4 overridden Ext.util.Format.fileSize for bigger sizes like GB and TB

gistfile1.js

/**
 * Overridden Ext.util.Format.fileSize for bigger sizes like GB and TB and support localized formats
 * 
 * Simple format for a file size (xxx bytes, xxx KB, xxx MB, xxx GB, xxx TB)
 * 
 * @param {Number/String}
 *            size The numeric value to format
 * @return {String} The formatted file size
 */
Ext.util.Format.fileSize = function(size, formatString) {
    var numberFormatString = formatString || '0.,00/i';
    if (size < 1024) {
        return Ext.util.Format.number(size, numberFormatString) + " B";
    } else if (size < 1048576) {
        return Ext.util.Format.number(Math.round(((size * 100) / 1024)) / 100, numberFormatString) + " KB";
    } else if (size < 1073741824) {
        return Ext.util.Format.number(Math.round(((size * 100) / 1048576)) / 100, numberFormatString) + " MB";
    } else if (size < 1099511627776) {
        return Ext.util.Format.number(Math.round(((size * 100) / 1073741824)) / 100, numberFormatString) + " GB";
    } else {
        return Ext.util.Format.number(Math.round(((size * 100) / 1099511627776)) / 100, numberFormatString) + " TB";
    }
};

how can I put this code into my secha architect 4.2? thanks in advance!!!