How can I run a debounced function from node command line?

I know what debounce does. I'd like to trigger it in node (by running a script with #!/usr/bin/env node), but I'm having trouble.

The code below should:

• Make doThingAfterDelay() which runs a simply function after it has been called once and not been called again for 100ms.
• Run doThingAfterDelay()
• Sleep (asynchronously) for 15 seconds, giving doThingAfterDelay() time to debounce and therefore execute.

However it doesn't work:

var log = console.log.bind(console),
  _ = require('lodash')


var doThingAfterDelay = _.debounce(function(){ 
  return 'foo'
}, 100);


log(doThingAfterDelay());

setTimeout(function(){
  log('Sleeping')
}, 15 * 1000)

It returns:

undefined
Sleeping

I expected:

foo
Sleeping

How can I make the debounced function run?

edit: I can get the desired output with:

var log = console.log.bind(console),
    _ = require('lodash')


var doThingAfterDelay= _.debounce(function(){
    log('foo')
}, 100);


doThingAfterDelay('one', 'two');

setTimeout(function(){
    log('Sleeping')
}, 15 * 1000)

But I do not understand why - and it is important that doThingAfterDelay() returns a real value.

via mikemaccana