--- title: "Frontend Mini-Game: Memory Leak Tuning Notes - 1" description: "A record of troubleshooting a memory leak in a Vue front-end animation game where memory usage continuously spiked to 1GB, and how Chrome DevTools was used to analyze and solve issues with an un-destroyed Lottie animation component and a Vue `keep-alive` cache issue." canonical_url: "https://blog.markkulab.net/en/post/javascript-memery-leak" author: "Mark Ku" author_url: "https://blog.markkulab.net/en/author/mark-ku" site: "Mark Ku's Tech Notes" date_published: "2022-01-24 01:01:01 +0800" category: "Frontend" tags: ["memory leak", "javascript", "vue", "lottie", "chrome devtools", "animation", "performance"] language: "en" license: "CC BY 4.0" license_url: "https://creativecommons.org/licenses/by/4.0/" attribution: "when reusing or quoting, credit the author and link back to the original" --- # Frontend Mini-Game: Memory Leak Tuning Notes - 1 ## The Problem While developing a small front-end animated web game, I noticed that after leaving the auto-play feature running overnight, memory usage would spike to 1GB. ![Developer console with CPU, JS heap, DOM node performance metrics](https://blog.markkulab.net/content/markku/posts/javascript-memery-leak/images/0PKf378.png) ## Before Investigating, Let's Understand Memory Leaks In computer science, a memory leak is a type of resource leak that occurs when a computer program incorrectly manages memory allocations in such a way that memory which is no longer needed is not released. (Wikipedia) ## Understanding the Browser's Garbage Collection Mechanism Browsers use a reference counting algorithm. Data that is no longer referenced is marked, and a periodic process runs to release that memory. ## Using Two Chrome Tools to Analyze the Memory Leak ### 1. Performance Monitor 1. Open Chrome > F12 > More Tools > Performance Monitor ![Chrome DevTools navigating to Performance monitor via More tools menu](https://blog.markkulab.net/content/markku/posts/javascript-memery-leak/images/Soh8NgQ.png)![Chrome DevTools Performance Monitor showing CPU and JS heap graphs](https://blog.markkulab.net/content/markku/posts/javascript-memery-leak/images/uYF50DH.png) ### 2. Memory Snapshot Open Chrome > F12 > Memory ![Chrome DevTools Memory panel showing JavaScript heap size and profiling](https://blog.markkulab.net/content/markku/posts/javascript-memery-leak/images/ui1UONh.png) ## Testing Methods 1. Refresh the page several times to see if memory usage drops (i.e., if it's being released). 2. Leave it running for a long time to see if memory usage grows. 3. Compare scenarios with and without `keep-alive`. 4. Use memory snapshots to analyze which JS objects are continuously growing. ## I Made Adjustments Primarily Based on This Article About Common Memory Leaks [Link](https://juejin.cn/post/7003598687851151397) ## In the End, I Made Two Adjustments ### 1. Manually call `destroy` before a custom component with the Lottie-web animation library is unmounted (via `v-if`). ``` beforeDestroy () { this.lottieAnimation.destroy('game-animation') this.lottieAnimation = null this.lottieApi = null } ``` ### 2. Because Vue's `keep-alive` only allows for [forcefully clearing](https://juejin.cn/post/6844903649517240328?fbclid=IwAR3w4SGnitm-uS6G3NK-Bh91KMjuQurFpBomdGtsn5nNxsDlDNEmJAYxt7M) the cache, I ultimately decided to remove it. This reduced average memory usage by 30 MB, and after running tests overnight, the memory spike issue was gone. ## In Conclusion After leaving it running overnight, the memory usage finally stopped spiking. --- ## About this article and its author Originally published on [Mark Ku's Tech Notes](https://blog.markkulab.net/en/post/javascript-memery-leak) License: [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/) — when reusing or quoting, credit the author and link back to the original ### About the author **[Mark Ku](https://blog.markkulab.net/en/author/mark-ku)** — Software Solution Provider - 10+ years senior software engineer, now an AI Builder - Focused on large-platform architecture — North-American e-commerce, AI SaaS subscription billing - Combining AI Agents and automation to build evolvable product foundations ### Free tools built by the author All of these are free to use: - [Free PDF Sign Tool](https://blog.markkulab.net/en/tools/pdf-sign): Online PDF sign tool — draw, type, or upload a signature, then drag, resize, and download. 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