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Node.js › Clustering & Worker Threads

How do you use SharedArrayBuffer to share memory directly between Node.js worker threads, and what are the safety considerations?

Advanced

Answer

SharedArrayBuffer allocates memory multiple worker threads can access directly without copying -- writes from one thread are immediately visible to others, requiring careful synchronization via Atomics to avoid race conditions from concurrent unsynchronized writes.
const sab = new SharedArrayBuffer(4);
const sharedArray = new Int32Array(sab);
Atomics.add(sharedArray, 0, 1);
console.log(Atomics.load(sharedArray, 0));
Real-world example A parallel computation service divides a matrix operation across four worker threads reading/writing different slices of the same SharedArrayBuffer, avoiding the overhead of copying data via message passing.

Common follow-ups: Why must operations on shared memory use Atomics rather than regular read/write?;What are the practical limits on data types inside a SharedArrayBuffer?

Advanced Node.js;Performance Optimization & Profiling
All 15 Clustering & Worker Threads questions