I need exactly the same function for adding late writes to the telemetry ping.

Comment on attachment 684705 [details] [diff] [review] patch Looks good, just a few small changes > class HangReports { ... >- const Telemetry::ProcessedStack::Module& GetModule(unsigned aIndex) const; >+ const CombinedStacks& getStacks() const; GetStacks instead >+static JSObject * >+CreateJSStackObject(JSContext *cx, const CombinedStacks &stacks); Put this near the top of the file >+ JSObject *durationArray = JS_NewArrayObject(cx, 0, nullptr); Check for nullptr >+ for (size_t i = 0, n = stacks.GetStackCount(); i < n; ++i) { >+ jsval duration = INT_TO_JSVAL(mHangReports.GetDuration(i)); >+ if (!JS_SetElement(cx, durationArray, i, &duration)) { >+ return NS_ERROR_FAILURE; >+ } >+ } Nitpick: declare "const size_t length = stacks.GetStackCount();" before the for-loop for readability. Same for others >- const uint32_t moduleCount = mHangReports.GetModuleCount(); >+ const uint32_t moduleCount = stacks.GetModuleCount(); Nit: size_t