Why Date/Time outputting "undefined" in node.js console?

Question

I'm attempting to get time to update with JavaScript in a Node.js console, in my function indexActiveTime I gather the hours, minutes, and seconds, and input them to a console.log that is suppose to output them as the current system time in a formatted 00:00:00; I call the function at the end and run the node.js program and for some reason I only get the following output.

undefined:undefined:undefined

undefined:undefined:undefined

undefined:undefined:undefined

I've attempted to throw it into certain variables, different concat methods, and the only results I've received are it outputting as the variable, like so.

${callActiveHours}:${callActiveMinutes}:${callActiveSeconds}

or

function getHours() { [native code] }:function getMinutes() { [native code] }:function getSeconds() { [native code] }

 function addZero(i) { if (i < 10) { i = "0" + 1; return i; } } function indexActiveTime() { var getIndexTime = new Date(); var callActiveHours = addZero(getIndexTime.getHours); var callActiveMinutes = addZero(getIndexTime.getMinutes); var callActiveSeconds = addZero(getIndexTime.getSeconds); console.log(callActiveHours + ":" + callActiveMinutes + ":" + callActiveSeconds); var activeTimeOut = setTimeout(indexActiveTime, 500); } indexActiveTime();

Answer 1

As the comments suggest:

1. The addZero function returns undefined when the condition i < 10 is false
2. The assignment i = '0' + 1 should be i = '0' + i
3. It's being passed a function reference rather than the result of calling a function so it's always false (and always returns undefined ).

 function addZero(i) { if (i < 10) { // Fix assignment i = "0" + i; return i; // Return i if condition is false } else { return i; } } function indexActiveTime() { var getIndexTime = new Date(); // Call methods, not just reference them var callActiveHours = addZero(getIndexTime.getHours()); var callActiveMinutes = addZero(getIndexTime.getMinutes()); var callActiveSeconds = addZero(getIndexTime.getSeconds()); console.log(callActiveHours + ":" + callActiveMinutes + ":" + callActiveSeconds); var activeTimeOut = setTimeout(indexActiveTime, 500); } indexActiveTime();

For how to create a timer that reasonably reliably runs at the required interval, see this answer.