jsc.HeapStats

interface HeapStats

• extraMemorySize: number

  Memory owned by objects in the heap but allocated outside of it, such as the contents of strings and ArrayBuffers. Included in both heapSize and heapCapacity.

• globalObjectCount: number

  Number of global objects in the heap: one for the main script, plus one for each node:vm context.

• heapCapacity: number

  Memory the heap has reserved for holding objects, plus extraMemorySize. At least heapSize; the difference is space that new objects can be allocated into without growing the heap.

• heapSize: number

  Size of the objects that survived the most recent garbage collection, plus extraMemorySize. The same number heapSize returns.

• objectCount: number

  Number of cells that survived the most recent garbage collection. Every garbage-collected allocation is a cell: objects, strings, functions, and JavaScriptCore's internal structures alike.

• objectTypeCounts: Record<string, number>

  Number of live cells of each type, keyed by JavaScriptCore's name for the type: JavaScript classes such as Object, Array, Promise, and Function, engine-internal types such as Structure and FunctionExecutable, and string for primitive strings. Ordered from most to least common; types with no live instances are omitted.

  Unlike objectCount, this includes cells allocated since the last garbage collection.

• protectedGlobalObjectCount: number

  How many of the global objects are protected by native code.

• protectedObjectCount: number

  Number of cells that native code has protected from being garbage collected. getProtectedObjects returns them.

• protectedObjectTypeCounts: Record<string, number>

  Like objectTypeCounts, but counting only the cells included in protectedObjectCount.