Using _.some | _.any properly for lo-dash or underscore

Question

I'm trying to see if any of the days are '01-01' ( the beginning of the year )

_.some(a.days, function(day){ console.log(day.date.format('DD-MM')) }, "01-01") 

Produces this array of dates in my console :

01-01 02-01 03-01 04-01 05-01 06-01 07-01 

So then I run without the console.log like so .. :

_.some(a.days, function(day){ day.date.format('DD-MM') }, "01-01") 

And it returns :

false 

Strange, eh? What do you think I'm doing incorrectly?

Answer 1

You've misunderstood what the last argument to _.some is. The documentation shows that it is the context, or scope, under which the iterator function runs, but it seems like you're trying to use it as a value for equality testing.

You'll need to explicitly execute the equality test yourself.

_.some(a.days, function(day) {     return day.date.format('DD-MM') === "01-01"; });