Function takeHeapSnapshot

lib/internal/debugger/inspect_repl.js:1044–1098

(filename = 'node.heapsnapshot')

      },

      takeHeapSnapshot(filename = 'node.heapsnapshot') {
        if (heapSnapshotPromise) {
          print(
            'Cannot take heap snapshot because another snapshot is in progress.',
          );
          return heapSnapshotPromise;
        }
        heapSnapshotPromise = new Promise((resolve, reject) => {
          const absoluteFile = Path.resolve(filename);
          const writer = FS.createWriteStream(absoluteFile);
          let sizeWritten = 0;
          function onProgress({ done, total, finished }) {
            if (finished) {
              print('Heap snapshot prepared.');
            } else {
              print(`Heap snapshot: ${done}/${total}`, false);
            }
          }

          function onChunk({ chunk }) {
            sizeWritten += chunk.length;
            writer.write(chunk);
            print(`Writing snapshot: ${sizeWritten}`, false);
          }

          function onResolve() {
            writer.end(() => {
              teardown();
              print(`Wrote snapshot: ${absoluteFile}`);
              heapSnapshotPromise = null;
              resolve();
            });
          }

          function onReject(error) {
            teardown();
            reject(error);
          }

          function teardown() {
            HeapProfiler.removeListener(
              'reportHeapSnapshotProgress', onProgress);
            HeapProfiler.removeListener('addHeapSnapshotChunk', onChunk);
          }

          HeapProfiler.on('reportHeapSnapshotProgress', onProgress);
          HeapProfiler.on('addHeapSnapshotChunk', onChunk);

          print('Heap snapshot: 0/0', false);
          PromisePrototypeThen(
            HeapProfiler.takeHeapSnapshot({ reportProgress: true }),
            onResolve, onReject);
        });
        return heapSnapshotPromise;
      },

      get watchers() {
        return watchers();