Question

I have the following code that obviously works but I am fairly sure there is a more terse way of expressing this in coffeescript:

  todos = []

  for i in [1..10]                                                                            
    todos.push App.store.find App.Todo, i 

Answer 1

todos = (App.store.find(App.Todo, i) for i in [1..10])

The enclosing parentheses indicate a list comprehension, which collects the return values into an array and returns it.

Consider the two following examples. The enclosing parentheses change how Coffeescript interprets the loop.

# With parentheses (list comprehension)
todos = (App.store.find(App.Todo, i) for i in [1..10])

# Without parentheses (plain old loop)
todos = App.store.find(App.Todo, i) for i in [1..10]

And the output:

// With parentheses
todos = (function() {
  var _i, _results;
  _results = [];
  for (i = _i = 1; _i <= 10; i = ++_i) {
    _results.push(App.store.find(App.Todo, i));
  }
  return _results;
})();

// Without parentheses
for (i = _i = 1; _i <= 10; i = ++_i) {
  todos = App.store.find(App.Todo, i);
}