It's a DRY thing. Often in JS, object literals assign their keys to values of the same name -- you'll see a lot of this: $.ajax(url, { data: data,

It's a DRY thing. Often in JS, object literals assign their keys to values of the same name -- you'll see a lot of this: $.ajax(url, { data: data, contentType: contentType, success: success, error: error }); ... not so nice. So as a first stab, you can clean it up like so: $.ajax url, {data, contentType, success, error} ... but it's especially nice in the context of destructuring assignment, like for your Node.js imports, for example. {spawn, exec} = require 'child_process'