Allows you to profile when the garbage collector runs, and how long it takes.
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Latest commit 13c07f9 Mar 14, 2017


A cross-platform (tested on Linux, Windows, and OSX) profiler for the v8 garbage collector running inside Node.js. It will emit an event after every GC cycle providing you information about the duration and type of cycle.

npm install gc-profiler


var profiler = require('gc-profiler');
profiler.on('gc', function (info) {

The info object contains the following properties:

Property Type Description
date Date The approximate start time of the GC cycle. This uses the c++ time library internally, which only has one-second resolution.
duration number The duration of the GC cycle in milliseconds.
type string Either Scavenge or MarkSweepCompact depending on the type of GC cycle.
forced boolean True for a forced cycle.
flags number The raw GCCallbackFlags provided from v8.

The profiler.GCCallbackFlags enumeration is provided to help decode the flags property.

profiler.GCCallbackFlags = {
  kNoGCCallbackFlags: 0,
  kGCCallbackFlagCompacted: 1 << 0, // this flag is never set in v8 versions >= 3.6.5
  kGCCallbackFlagConstructRetainedObjectInfos: 1 << 1,
  kGCCallbackFlagForced: 1 << 2