From bc5004755cde2f7f17c9f6b6fbe8f699f4a1b734 Mon Sep 17 00:00:00 2001
From: Calvin Metcalf <cmetcalf@appgeo.com>
Date: Thu, 30 Jan 2014 11:07:57 -0500
Subject: [PATCH] (#1264 pouchdb/mapreduce#37) - document eval avoidance

---
 docs/api.md | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/docs/api.md b/docs/api.md
index 419108360e..71cafd804f 100644
--- a/docs/api.md
+++ b/docs/api.md
@@ -541,6 +541,36 @@ db.query({map: map}, {reduce: false}, function(err, response) { });
 }
 {% endhighlight %}
 
+if you pass a function to db.query and give it 'emit' as the second argument, then you can use a closure, (otherwise we have to use eval to bind emit)
+{% highlight js %}
+//BAD! will throw error
+(function (id) {
+  db.query(function(doc) {
+    if(doc._id === id) {
+      emit(doc);
+    }
+  }).then(dance);
+}(something));
+
+//will be fine
+(function (id) {
+  db.query(function(doc, emit) {
+    if(doc._id === id) {
+      emit(doc);
+    }
+  }).then(dance);
+}(something));
+{% endhighlight %}
+You don't actuallly have to call them by those names though
+{% highlight js %}
+(function (id) {
+  db.query(function(thisIs, awesome) {
+    if(thisIs._id === id) {
+      awesome(thisIs);
+    }
+  }).then(dance);
+}(something));
+{% endhighlight %}
 **Notes:**
 
 1. Local databases do not currently support view caching; everything is a live view.