Array iteration fun in CoffeeScript

array_iteration_fun.coffee

# Say you want to iterate over a variable that might be an array or null/undefined,
# you can do this:

for order in orders or []
  # Do something with orders
  
# This simply iterates over the empty array if book is null or undefined. Handy if
# you have an object like this:

customers = {
  1934: [{Order ...}, {Order ...}, {Order ...}],
  1942: null,
  1963: [{Order ...}]
}

# And you want to iterate over it to show orders per customer:
for customer, customer_orders of customers
  order.checked = true for order in customer_orders or []
  
# Pretty cool. Although it'd be preferable to have nulls cast to Arrays in the
# customers object to begin with!