import MemoryMonitor, {getMemorySnapshot} from 'mem-pressure';

const monitor = new MemoryMonitor({threshold: 0.9, interval: 10_000});

monitor.addEventListener('pressure', event => {
	console.log('Memory pressure detected!');
	console.log(`Heap usage: ${(event.detail.heapUsedRatio * 100).toFixed(1)}%`);
});

monitor.start();

// Get a one-off snapshot
const snapshot = getMemorySnapshot();
console.log(snapshot.heapUsedRatio);

// Stop monitoring
monitor.stop();

API

MemoryMonitor(options?)

Creates a new memory monitor instance. Extends EventTarget.

options

Type: object

threshold

Type: number
Default: 0.85

Heap usage ratio (0-1) at which to emit 'pressure' events.

interval

Type: number
Default: 5000

Polling interval in milliseconds.

Events

`'pressure'`

Emitted when heapUsed / heapTotal exceeds the threshold. The listener receives a CustomEvent with detail set to a MemorySnapshot object.

.start()

Start monitoring memory usage. Returns this for chaining.

.stop()

Stop monitoring memory usage. Returns this for chaining.

[Symbol.dispose]()

Calls .stop(). Enables use with the using declaration.

getMemorySnapshot()

Returns a MemorySnapshot object with the following properties:

rss — Resident Set Size in bytes
heapTotal — Total size of the allocated heap in bytes
heapUsed — Actual memory used during execution in bytes
external — Memory used by C++ objects bound to JavaScript objects in bytes
arrayBuffers — Memory allocated for ArrayBuffer and SharedArrayBuffer in bytes
heapUsedRatio — Ratio of heapUsed to heapTotal (0-1)