--- title: Important JavaScript concepts | daily.dev description: The important JavaScript concepts that programmers need to be familiar with are covered in this article. Many developers obtain surprising outputs when... canonical: https://daily.dev/posts/important-javascript-concepts-fue7jx8r2 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Important JavaScript concepts | daily.dev og:description: The important JavaScript concepts that programmers need to be familiar with are covered in this article. Many developers obtain surprising outputs when... og:url: https://daily.dev/posts/important-javascript-concepts-fue7jx8r2 og:image: https://api.daily.dev/og/posts/FUe7Jx8R2.png og:image:alt: Important JavaScript concepts og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Important JavaScript concepts **[Community Picks](https://daily.dev/sources/community)** · 6 min read · 128 upvotes · 10 comments ## Summary The important JavaScript concepts that programmers need to be familiar with are covered in this article. Many developers obtain surprising outputs when unfamiliar with the idea of hoisting in Javascript. The above programs work as below and the output will be undefined. The main benefits of using IIFE are data privacy and quick code execution. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Community discussion Top comments from developers on daily.dev. **@anubhavbhatt** · 1 upvotes > # Great article to give knowledge on the topics of javascript **@fatali** · 1 upvotes > 👍 **@lucasgoncalves** · 1 upvotes > Nice article!!! **@shreyash\_singh** · 1 upvotes > Nice Article **@sohanemon** · 1 upvotes > Great job ## Similar posts on daily.dev - [Don’t just attend KubeCon \+ CloudNativeCon, Merge Forward your experience\!](https://daily.dev/posts/don-t-just-attend-kubecon-cloudnativecon-merge-forward-your-experience--l0rpp73x8) · CNCF · 1 upvotes · 0 comments - [Announcing H2 2026 KCDs](https://daily.dev/posts/announcing-h2-2026-kcds-m96goajm1) · CNCF · 1 upvotes · 0 comments - [Two months of Open Community Groups](https://daily.dev/posts/two-months-of-open-community-groups-asf52zhbs) · CNCF · 0 upvotes · 0 comments - [CNCF Unveils Schedule for KubeCon \+ CloudNativeCon Europe 2026](https://daily.dev/posts/cncf-unveils-schedule-for-kubecon-cloudnativecon-europe-2026-ikhcoa5cb) · CNCF · 2 upvotes · 0 comments - [CNCF Debuts KubeCon \+ CloudNativeCon Japan 2026 Schedule](https://daily.dev/posts/cncf-debuts-kubecon-cloudnativecon-japan-2026-schedule-xp5pyudub) · CNCF · 1 upvotes · 0 comments --- Tags: [#react](https://daily.dev/tags/react), [#javascript](https://daily.dev/tags/javascript) [View this post on daily.dev](https://daily.dev/posts/important-javascript-concepts-fue7jx8r2) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Important JavaScript concepts","url":"https://daily.dev/posts/important-javascript-concepts-fue7jx8r2","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/important-javascript-concepts-fue7jx8r2"},"datePublished":"2022-12-20T16:31:16.319Z","dateModified":"2023-12-07T12:02:45.284Z","description":"The important JavaScript concepts that programmers need to be familiar with are covered in this article. 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