Is there a simple way to use Underscorejs to achieve this?

Question

I have an object, having key and values. I'd like to pick the object and call the appropriate function from the key:

var requireViews = {
            "breadCrumbView": true,
            "headerView": false,
            "footerView": false
        };

var that = this;

    _.each(requireViews, function(value, key){
                    if(value){ //if true?
                        if(_.functions(that, key)) that[key](); //checking is that function, and calling the function
                    }
                })

Is it ok or can we minimize it further?

Answer 1

If you add a filterObject mixin (this is the one I usually use), it will be easy

_.mixin({
    filterObject: function(obj, predicate, context) {
        return _.reduce(obj, function(memo, val, key) {
            if (predicate.call(context, val, key, memo)) memo[key] = val;
            return memo;
        }, {});
    }
});

Now its simple and elegant :)

_.invoke(this, _.values(_.filterObject(requireViews, Boolean)));

If you like underscores you can use the ridiculous algorithm below (don't do it!)

_.invoke(this, _.map(_.filter(_.pairs(requireViews), _.partial(_.every, _, Boolean)), _.first))

Answer 2

To be honest, I'd skip underscore for this, and just do

for(var func in requireViews) {
  if(requireViews[func] && typeof this[func] === 'function') {
    this[func]();
  }
}

Otherwise, there are many different ways to go about it.

Here's a needlessly complex one, for instance:

var target = this;
_.chain(requireViews)
  .keys()
  .filter(function (func) { return requireViews[func] })
  .intersection(_.functions(this))
  .each(function (func) { target[func]() });