https://coderrob.com/tags/closures/Recent content in Closures on CoderrobHugoen-USMon, 27 Apr 2026 10:00:00 -0500https://coderrob.com/posts/javascript-closures-and-modified-closures-explained/Mon, 27 Apr 2026 10:00:00 -0500https://coderrob.com/posts/javascript-closures-and-modified-closures-explained/<p>Closures show up any time a JavaScript function uses a variable defined from outside its own curly braces.</p> <p>That makes them common in callbacks, event handlers, timers, factory functions, and plenty of code that passes functions around.</p> <p>This post is about two questions:</p> <ol> <li><strong>What is a closure?</strong></li> <li><strong>What happens when a closed-over variable is modified before the function uses it?</strong></li> </ol> <p>The short version:</p> <blockquote> <p>A closure happens when a function keeps access to variables from its surrounding scope, even after that outer scope has finished running.</p>