how to get a model by array params from a collecti

问题:

I have a model like this:

model = 
    from: "[e-mail]"
    id: 1
    to: [[e-mail]]

and I have a collection containing these kind of models. The collection needs to filter by from. I know _.where an underscore.js function. I am using it like this:

fromIds = _.pluck _.where(msgs, from : login), 'msgId' 

and need to filter by 'to' as well:

toIds = _.pluck _.where(msgs, to : login), 'msgId' 

it does not work, because to is an array. How can I filter by to ? I would be grateful if someone helped me out !

回答1:

At that point you need to use _.filter. If you look at the source code you can see that _.where is just a helpful wrapper around _.filter. _.where is good for simple filtering based on primitive comparison, but anything more complex you will have to write yourself.

# Filter for messages that contain the target address.
matchedTo = _.filter msgs, (msg) -> _.contains msg.to, login

# Pluck as usual
toIds = _.pluck matchedTo, 'msgId'