Is JavaScript a memory-safe language? 

Product Strategy
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mins read

JavaScript, as a language, is considered relatively memory-safe, especially when compared to lower-level languages like C or C++. This is because JavaScript is executed within a managed runtime environment (such as a web browser or Node.js) that handles memory allocation, garbage collection, and other memory management tasks automatically. This managed environment helps to prevent common memory safety issues such as buffer overflows, memory leaks, and dangling pointers that are more prevalent in unmanaged languages.

However, "memory safe" does not mean that JavaScript is immune to all memory-related issues. Developers can still write JavaScript code that leads to memory leaks, especially in complex applications or when interacting with the Document Object Model (DOM) in web browsers. These leaks often occur due to unintentional references that prevent the garbage collector from freeing unused memory.

In addition, JavaScript’s runtime engine can be a source of vulnerabilities. For example, in December 2022, the Google Chrome team was forced to release a patch that resolved a severe zero-day flaw where malicious users could corrupt the heap stored in memory.

In summary, while JavaScript's runtime environment provides a higher level of memory safety than languages without automatic memory management, developers need to be mindful of coding patterns that can lead to memory inefficiencies or leaks and ensure they are running the latest version of runtime engines with the latest security patches.