Add stream index to errors

README.md

@@ -35,6 +35,8 @@ setTimeout(function() {
 }, 1000)
 ```
 
+If an `err` is returned in the callback it will have a `streamIndex` property indicating from which stream the error originated from.
+
 You can use pump to pipe more than two streams together as well
 
 ``` js

index.js

@@ -68,7 +68,10 @@ var pump = function () {
     var reading = i < streams.length - 1
     var writing = i > 0
     return destroyer(stream, reading, writing, function (err) {
-      if (!error) error = err
+      if (!error && err) {
+        error = err
+        error.streamIndex = i
+      }
       if (err) destroys.forEach(call)
       if (reading) return
       destroys.forEach(call)

test-node-error.js

@@ -0,0 +1,23 @@
+var pump = require('./index')
+
+var rs = require('fs').createReadStream('/dev/random')
+var ws = require('fs').createWriteStream('/dev/null')
+
+var callbackCalled = false
+
+var check = function (err) {
+  if (err && err.streamIndex === 0) {
+    console.log('test-node-error.js passes')
+    clearTimeout(timeout)
+  }
+}
+
+setTimeout(function () {
+  rs.destroy(new Error('premature close'))
+}, 1000)
+
+pump(rs, ws, check)
+
+var timeout = setTimeout(function () {
+  throw new Error('timeout')
+}, 5000)