Out of memory errors usually mean the app exceeds its memory limit due to large datasets or inefficient data handling. Optimizing memory usage is key.

The 'Process out of memory' error in Node.js occurs when the application’s memory usage exceeds the maximum heap size, often due to large datasets, inefficient memory handling, or memory leaks. Node.js allocates a default memory limit for each process, and when applications handle large datasets or retain data in memory without efficient management, the app can exhaust available memory quickly. To address this, identify memory-intensive operations by using heap snapshots and profiling to locate the exact areas where memory usage peaks. If handling large datasets, consider streaming data rather than loading it all at once, as streaming allows you to process data in smaller, manageable chunks without overwhelming memory. For cases where multiple objects or large arrays accumulate, clearing unused references promptly can prevent memory from being consumed unnecessarily. Additionally, if caching data, ensure that cache size is carefully managed or use in-memory stores like Redis for more efficient storage management. Regularly test and profile your application under various load scenarios to ensure memory usage is kept within manageable limits.