--- title: Angular Spreadsheet Freezing on Large Excel Imports?... description: Large Excel imports in Angular apps freeze the browser because synchronous XLSX parsing blocks the main thread. Three techniques using Syncfusion Angular... canonical: https://daily.dev/posts/angular-spreadsheet-freezing-on-large-excel-imports-here-s-the-fix-yxh3xdxce twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Angular Spreadsheet Freezing on Large Excel Imports? Here’s the Fix | daily.dev og:description: Large Excel imports in Angular apps freeze the browser because synchronous XLSX parsing blocks the main thread. Three techniques using Syncfusion Angular... og:url: https://daily.dev/posts/angular-spreadsheet-freezing-on-large-excel-imports-here-s-the-fix-yxh3xdxce og:image: https://api.daily.dev/og/posts/YxH3XdxcE.png og:image:alt: Angular Spreadsheet Freezing on Large Excel Imports? Here’s the Fix 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. # Angular Spreadsheet Freezing on Large Excel Imports? Here’s the Fix **[Syncfusion](https://daily.dev/sources/syncfusion)** · 9 min read · 0 upvotes · 0 comments ## Summary Large Excel imports in Angular apps freeze the browser because synchronous XLSX parsing blocks the main thread. Three techniques using Syncfusion Angular Spreadsheet Editor can fix this: (1) Use WorkbookParseOptions with IgnoreStyle and IgnoreFormat to skip formatting overhead and load only raw cell data; (2) Set MaximumDataLimit and MaximumFileSize thresholds server-side to block oversized uploads before they crash the app; (3) Use openFromJson with selective deserialization to avoid repeated XLSX parsing. Performance benchmarks show 500,000 cells can be imported in ~4 seconds with near-linear scaling. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Why Your Browser Freezes with Large Excel Files in JavaScript Spreadsheet Apps and How to Fix It](https://daily.dev/posts/why-your-browser-freezes-with-large-excel-files-in-javascript-spreadsheet-apps-and-how-to-fix-it-tbekzh4sp) · Syncfusion · 1 upvotes · 0 comments - [Why Freeze Panes Break Virtual Scrolling in Angular Spreadsheets](https://daily.dev/posts/why-freeze-panes-break-virtual-scrolling-in-angular-spreadsheets-7h8yk6vk2) · Syncfusion · 0 upvotes · 0 comments - [What’s the Best Way to Import Excel and CSV Files into a React App?](https://daily.dev/posts/what-s-the-best-way-to-import-excel-and-csv-files-into-a-react-app--hvbonmezn) · Syncfusion · 0 upvotes · 0 comments --- Tags: [#performance](https://daily.dev/tags/performance), [#angular](https://daily.dev/tags/angular) [View this post on daily.dev](https://daily.dev/posts/angular-spreadsheet-freezing-on-large-excel-imports-here-s-the-fix-yxh3xdxce) ```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":"Angular Spreadsheet Freezing on Large Excel Imports? 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