FATAL ERROR: Ineffective mark-compacts near heap limit Allocation failed – JavaScript heap out of memory.

Last updated on May 19th, 2024 at 12:46 pm

The error message “FATAL ERROR: Ineffective mark-compacts near heap limit Allocation failed – JavaScript heap out of memory” in Node.js indicates that the Node.js process has run out of memory while attempting to perform garbage collection, resulting in a fatal crash.

Here are some steps you can take to address this issue:

1. Increase Memory Allocation: You can allocate more memory to the Node.js process using the --max-old-space-size flag. For example:

node --max-old-space-size=4096 your_script.js

This command allocates 4GB of memory to the Node.js process. Adjust the value as needed based on your system’s resources.

To set the --max-old-space-size flag in the package.json file, you can use the node field within the "scripts" section. Here’s how you can do it:

  "name": "your_project",
  "version": "1.0.0",
  "scripts": {
    "start": "node --max-old-space-size=4096 your_script.js"

In this example, when you run npm start or yarn start in your terminal, it will execute the node command with the specified --max-old-space-size flag and your script (your_script.js). Adjust the value 4096 according to your memory requirements.

2. Optimize Memory Usage: Review your code to identify any memory-intensive operations or memory leaks. Optimize your code to reduce memory usage by freeing up memory when it’s no longer needed, using streams instead of loading entire files into memory, or implementing caching strategies.

3. Use a Memory Profiler: Utilize tools like the built-in Node.js --inspect flag with Chrome DevTools or third-party packages like heapdump or memwatch-next to analyze memory usage and identify memory leaks in your application.

4. Upgrade Node.js: Ensure that you are using the latest stable version of Node.js, as newer versions often come with performance improvements and bug fixes that may help mitigate memory-related issues.

5. Split Workload: If your application performs heavy computations or processes large datasets, consider splitting the workload into smaller chunks or parallelizing tasks to distribute memory usage more evenly.

6. Increase System Memory: If possible, consider adding more physical memory (RAM) to your system to provide additional resources for Node.js to utilize.

By implementing these steps, you should be able to mitigate the “JavaScript heap out of memory” error in your Node.js application and improve its stability and performance.