The javascript one seems pretty simple, just localStorage.clear().
Is there anything similar to that for the backbone localstorage, and if not, can someone point me
Just iterating over the collection and calling destroy on each element is not save in any case. The reason is iterating over collection modified at the same time can produce unexpected results.
It is better to first clone the collection and iterate over this clone. Checkout this.each not iterating through collection correctly for further details.
Example:
_.chain(Todos.models).clone().each(function(model){
console.log('deleting model ' + model.id);
model.destroy();
});