Initial import

node_modules/lead/index.js

@@ -0,0 +1,50 @@
+'use strict';
+
+function hasListeners(stream) {
+  return !!(stream.listenerCount('readable') || stream.listenerCount('data'));
+}
+
+function sink(stream) {
+  var sinkAdded = false;
+
+  function addSink() {
+    if (sinkAdded) {
+      return;
+    }
+
+    if (hasListeners(stream)) {
+      return;
+    }
+
+    sinkAdded = true;
+    stream.resume();
+  }
+
+  function removeSink(evt) {
+    if (evt !== 'readable' && evt !== 'data') {
+      return;
+    }
+
+    if (hasListeners(stream)) {
+      sinkAdded = false;
+    }
+
+    process.nextTick(addSink);
+  }
+
+  function markSink() {
+    sinkAdded = true;
+  }
+
+  stream.on('newListener', removeSink);
+  stream.on('removeListener', removeSink);
+  stream.on('piping', markSink);
+
+  // Sink the stream to start flowing
+  // Do this on nextTick, it will flow at slowest speed of piped streams
+  process.nextTick(addSink);
+
+  return stream;
+}
+
+module.exports = sink;