--- title: JavaScript SOLID Principles: How to Write Maintainable Code description: Learn how to apply SOLID principles to write maintainable code in JavaScript. Explore the single responsibility principle, open-closed principle, Liskov... canonical: https://daily.dev/posts/javascript-solid-principles-how-to-write-maintainable-code-knkof7hxm twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: JavaScript SOLID Principles: How to Write Maintainable Code | daily.dev og:description: Learn how to apply SOLID principles to write maintainable code in JavaScript. Explore the single responsibility principle, open-closed principle, Liskov... og:url: https://daily.dev/posts/javascript-solid-principles-how-to-write-maintainable-code-knkof7hxm og:image: https://api.daily.dev/og/posts/knkof7hXM.png og:image:alt: JavaScript SOLID Principles: How to Write Maintainable Code 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. # JavaScript SOLID Principles: How to Write Maintainable Code **[Syncfusion](https://daily.dev/sources/syncfusion)** · [@sureshmohan](https://daily.dev/sureshmohan) · 7 min read · 441 upvotes · 13 comments ## Summary Learn how to apply SOLID principles to write maintainable code in JavaScript. Explore the single responsibility principle, open-closed principle, Liskov substitution principle, interface segregation principle, and dependency inversion principle. ## 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. **@lexlohr** · 15 upvotes > The example for the Liskov substitution principle illustrates beautifully why you should treat principles as a guideline rather than a law set in stone. > > By letting Ostrich inherit from Animal rather than Bird, you are shaping your code after this principle instead of after reality; checking if Ostrich was an instance of Bird will fail. Also, even birds capable of flight have the ability to walk. > > So, the solution is to either have an extra attribute "flightless" to indicate those birds that will throw an error if asked to fly, or to have two subclasses for Bird, FlyingBird and... **@missadibas** · 4 upvotes > not for beginners. my brain aches only after reading what SOLID stands for. *crying in noob* **@anmolbaranwal** · 3 upvotes > Wow, I must say I'm thoroughly impressed with the way you've broken down the SOLID principles in your article. You've made it so simple and easy to understand, even for developers who may be new to the concept. > > It's crystal clear that adhering to SOLID principles is crucial for achieving top-notch code quality and maintainability. And let's be honest, who wouldn't want that? By implementing these principles, developers can easily avoid common pitfalls that lead to spaghetti code and headaches down the line. > > > Trust me, you won't regret it :) **@correiajpv** · 2 upvotes > SOLID principles are a must-know for any serious developer. This article does a great job of explaining how to apply these principles specifically in JavaScript, making it a valuable resource for front-end and back-end developers alike. The code examples are especially helpful in illustrating the concepts. Highly recommended! **@bonaogeto** · 2 upvotes > Here is another great series of JavaScript basics tutorials. I'll appreciate it if someone takes the initiative to submit them here > > https://hojaleaks.com/series/javascript-101 ## 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 --- Tags: [#general-programming](https://daily.dev/tags/general-programming), [#javascript](https://daily.dev/tags/javascript) [View this post on daily.dev](https://daily.dev/posts/javascript-solid-principles-how-to-write-maintainable-code-knkof7hxm) ```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":"JavaScript SOLID Principles: How to Write Maintainable Code","url":"https://daily.dev/posts/javascript-solid-principles-how-to-write-maintainable-code-knkof7hxm","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/javascript-solid-principles-how-to-write-maintainable-code-knkof7hxm"},"datePublished":"2023-04-10T11:31:56.544Z","dateModified":"2024-04-15T09:00:10.448Z","description":"Learn how to apply SOLID principles to write maintainable code in JavaScript. Explore the single responsibility principle, open-closed principle, Liskov...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/17ff107e28771459a990c8f642bf7420?_a=AQAEufR","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/17ff107e28771459a990c8f642bf7420?_a=AQAEufR","isAccessibleForFree":true,"articleSection":"Syncfusion","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Person","name":"Suresh Mohan","url":"https://daily.dev/sureshmohan","image":"https://lh3.googleusercontent.com/a-/AOh14GiORQm3okwNI9Z01tYDa4YELb6j3F-hP-fbPVbSves=s100","interactionStatistic":{"@type":"InteractionCounter","interactionType":{"@type":"EndorseAction"},"userInteractionCount":1970}},"commentCount":13,"discussionUrl":"https://daily.dev/posts/javascript-solid-principles-how-to-write-maintainable-code-knkof7hxm","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":441},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":13}],"keywords":"general-programming,javascript","timeRequired":"PT7M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Syncfusion","item":"https://daily.dev/sources/syncfusion"},{"@type":"ListItem","position":3,"name":"JavaScript SOLID Principles: How to Write Maintainable Code"}]} {"@context":"https://schema.org","@type":"WebPage","@id":"https://daily.dev/posts/javascript-solid-principles-how-to-write-maintainable-code-knkof7hxm","comment":[{"@type":"Comment","text":"The example for the Liskov substitution principle illustrates beautifully why you should treat principles as a guideline rather than a law set in stone.\nBy letting Ostrich inherit from Animal rather than Bird, you are shaping your code after this principle instead of after reality; checking if Ostrich was an instance of Bird will fail. Also, even birds capable of flight have the ability to walk.\nSo, the solution is to either have an extra attribute “flightless” to indicate those birds that will throw an error if asked to fly, or to have two subclasses for Bird, FlyingBird and FlightlessBird.\nPlease remember, your code is meant to be maintained by humans, so don’t throw hundreds of lines of unnecessary boilerplate in their way.","datePublished":"2023-04-11T08:04:49.189Z","url":"https://daily.dev/posts/knkof7hXM#c-ftXLWn0WY","author":{"@type":"Person","name":"Alex Lohr","url":"https://daily.dev/lexlohr","image":"https://lh3.googleusercontent.com/a-/AFdZuco9x-ZOIY48Y3l6mwE_djy1FceBbHU5BawnEvGKKQ=s100"},"interactionStatistic":{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":15}},{"@type":"Comment","text":"not for beginners. my brain aches only after reading what SOLID stands for. crying in noob","datePublished":"2023-04-12T07:38:54.390Z","url":"https://daily.dev/posts/knkof7hXM#c-uKZRx64O5","author":{"@type":"Person","name":"MissAdibas","url":"https://daily.dev/missadibas","image":"https://avatars.githubusercontent.com/u/91949174?v=4"},"interactionStatistic":{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":4}},{"@type":"Comment","text":"Wow, I must say I’m thoroughly impressed with the way you’ve broken down the SOLID principles in your article. You’ve made it so simple and easy to understand, even for developers who may be new to the concept.\nIt’s crystal clear that adhering to SOLID principles is crucial for achieving top-notch code quality and maintainability. And let’s be honest, who wouldn’t want that? By implementing these principles, developers can easily avoid common pitfalls that lead to spaghetti code and headaches down the line.\n\nTrust me, you won’t regret it :)","datePublished":"2023-04-11T15:11:39.208Z","url":"https://daily.dev/posts/knkof7hXM#c-tYs66HscS","author":{"@type":"Person","name":"Anmol Baranwal","url":"https://daily.dev/anmolbaranwal","image":"https://avatars.githubusercontent.com/u/74038190?v=4"},"interactionStatistic":{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":3}},{"@type":"Comment","text":"SOLID principles are a must-know for any serious developer. This article does a great job of explaining how to apply these principles specifically in JavaScript, making it a valuable resource for front-end and back-end developers alike. The code examples are especially helpful in illustrating the concepts. Highly recommended!","datePublished":"2023-04-12T11:28:00.510Z","url":"https://daily.dev/posts/knkof7hXM#c-JxmgsbJSW","author":{"@type":"Person","name":"João Correia","url":"https://daily.dev/correiajpv","image":"https://avatars.githubusercontent.com/u/16155781?v=4"},"interactionStatistic":{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":2}},{"@type":"Comment","text":"Here is another great series of JavaScript basics tutorials. I’ll appreciate it if someone takes the initiative to submit them here\nhttps://hojaleaks.com/series/javascript-101","datePublished":"2023-04-16T12:17:00.749Z","url":"https://daily.dev/posts/knkof7hXM#c-eoCVOIMm5","author":{"@type":"Person","name":"Bonaventure Ogeto","url":"https://daily.dev/bonaogeto","image":"https://avatars.githubusercontent.com/u/39027629?v=4"},"interactionStatistic":{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":2}}]} ```