express中的app.locals的问题

需求是这样的，将得到的数字（秒）转成…分…秒，我写了一个formatSeconds函数，想在jade模版中使用 函数

function formatSeconds(value) {
    var theTime = parseInt(value);// 秒 
    var theTime1 = 0;// 分 
    var theTime2 = 0;// 小时 
    // alert(theTime); 
    if (theTime > 60) {
        theTime1 = parseInt(theTime / 60);
        theTime = parseInt(theTime % 60);
        // alert(theTime1+"-"+theTime); 
        if (theTime1 > 60) {
            theTime2 = parseInt(theTime1 / 60);
            theTime1 = parseInt(theTime1 % 60);
        }
    }
    var result = "" + parseInt(theTime) + "秒";
    if (theTime1 > 0) {
        result = "" + parseInt(theTime1) + "分" + result;
    }
    if (theTime2 > 0) {
        result = "" + parseInt(theTime2) + "小时" + result;
    }
    return result;
}

module.exports = formatSeconds

express的app文件

app.locals.formatSeconds = require("/static/js/lib/formatSeconds.js")

jade中的使用

#{formatSeconds(totalTime)}

问题：报错：formatSeconds is not a function

请问是我的用法错了吗还是怎样，求解