1 files changed, 71 insertions, 0 deletions
diff --git a/js/ansi/newlines.js b/js/ansi/newlines.js
new file mode 100644
index 0000000..4e37a0a
--- /dev/null
+++ b/js/ansi/newlines.js
@@ -0,0 +1,71 @@
+
+/**
+ * Accepts any node Stream instance and hijacks its "write()" function,
+ * so that it can count any newlines that get written to the output.
+ *
+ * When a '\n' byte is encountered, then a "newline" event will be emitted
+ * on the stream, with no arguments. It is up to the listeners to determine
+ * any necessary deltas required for their use-case.
+ *
+ * Ex:
+ *
+ *   var cursor = ansi(process.stdout)
+ *     , ln = 0
+ *   process.stdout.on('newline', function () {
+ *    ln++
+ *   })
+ */
+
+/**
+ * Module dependencies.
+ */
+
+var assert = require('assert')
+var NEWLINE = '\n'.charCodeAt(0)
+
+function emitNewlineEvents (stream) {
+  if (stream._emittingNewlines) {
+    // already emitting newline events
+    return
+  }
+
+  var write = stream.write
+
+  stream.write = function (data) {
+    // first write the data
+    var rtn = write.apply(stream, arguments)
+
+    if (stream.listeners('newline').length > 0) {
+      var len = data.length
+        , i = 0
+      // now try to calculate any deltas
+      if (typeof data == 'string') {
+        for (; i<len; i++) {
+          processByte(stream, data.charCodeAt(i))
+        }
+      } else {
+        // buffer
+        for (; i<len; i++) {
+          processByte(stream, data[i])
+        }
+      }
+    }
+
+    return rtn
+  }
+
+  stream._emittingNewlines = true
+}
+module.exports = emitNewlineEvents
+
+
+/**
+ * Processes an individual byte being written to a stream
+ */
+
+function processByte (stream, b) {
+  assert.equal(typeof b, 'number')
+  if (b === NEWLINE) {
+    stream.emit('newline')
+  }
+}