Question

underscore.js is handling the templating on the page, and I have jQuery on my page also.

I have an array that looks something like this:

orders = [{q:5},{q:5},{q:5},{q:5},{q:5}];

Now on the page I want the sum of q printed, but I cannot get it to work.

I tried a lot of code snippets, but none of them seem to work. The one I thought had do work is this one:

<td><% print( _.reduce(orders.q), function(memo, num){ return memo + num; }, 0 ) %></td>

It’s from the page of underscore itself.

This piece of code gives me:

undefined is not a function;

Answer 1

orders.q looks for a property q on the array orders — so orders.q is most likely returning undefined, which is indeed not a function.

You probably want to pass _.pluck(orders, 'q'), which returns an array of the values of q for each item in orders, to _.reduce. And double-check your parentheses:

_.reduce(orders.q, function(memo, num){ return memo + num; }, 0)