Mnemonic for remembering Coffeescript's `in` vs `of`
coffeescript
Solution
This sentence of the linked documentation seems particularly apt:
Comprehensions can also be used to iterate over the keys and values in an object. Use of to signal comprehension over the properties of an object instead of the values in an array.
Basically, think "items `in` an array", "properties `of` an object".
Problem
I've been using Coffeescript all day every day for three months. I love it. There are a few little learning niggles with how it translates to JS, but I've gotten over all of them except one: How do I remember whether to use `in` or `of` when iterating over loops and arrays? http://coffeescript.org/#loops Sometimes I need the key and value, sometimes I only need the value. Both `of` and `in` work on both arrays and objects to iterate. Can someone recommend a mnemonic for remembering which one is which? This would be very valuable to me. I'm tired of going to the doc site for this same thing over and over again :) Example from a different domain: I always remember that west is on the left and east is on the right of a compass because it spells "we".