What's this JavaScript syntax?
javascript
Solution
It looks like someone has made a lot of effort to make this very hard to read.
If I interpret it right, it does something like this:
- call the match method.
- it returns an array of matches, or nothing (null, undefined?). If it doesn't return anything, default to an empty array.
- Of the array, get the element with index 'regDefiniation.index'.
- If that item doesn't exist (which can be the case for matches, and will always be the case for the empty default array), return null.
Problem
I am new to JavaScript. The following code is from some production codebase. The regDefinition is passed in JSON form. But I am not quite sure about the syntax in the method body. Especially the `||` and `[]` parts. ``` function getCookieValue(regDefinition) { return (document.cookie.match(regDefiniation.regEx) || [])[regDefiniation.index] || null; } ```