Assigning multiple values at once

Let's look at a handy shorthand for assigning values to variables. CoffeeScript offers a feature called destructuring assignment . This is a fancy term that means you can assign multiple variables from an array or object using a single expression.

[first, second] = ["horse", "cart"]
console.log "Don't put the #{second} before the #{first}."

We were able to assign the variables first and second in one expression simply by adding square brackets around them. Looking at the compiled JavaScript shows us how CoffeeScript achieves this:

_ref = ["horse", "cart"], first = _ref[0], second = _ref[1];

It's using a temporary variable for reference, and then assigning the variables one at a time using array indexes. This looks ...

Get CoffeeScript Application Development now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.