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Use Array#forEach instead of for .. in #69

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44 changes: 22 additions & 22 deletions share/doc/src/ddocs.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -48,25 +48,23 @@ Map functions

:param doc: Processed document object.

Map functions should take a single argument as document object and optionally
emits paired values also known as `key` and `value`. Since JavaScript
doesn't support generators and ``yield`` statement it is emulated via :func:`emit`:
Map functions accept a single document as the argument and (optionally) :func:`emit`
key/value pairs that are stored in a view.

.. code-block:: javascript

function(doc){
if (!doc.tags || !isArray(doc.tags) || !doc.type || doc.type != 'post'){
return;
}
for (var idx in doc.tags){
emit(doc.tags[idx].toLower(), 1);
function (doc) {
if (doc.type === 'post' && doc.tags && Array.isArray(doc.tags)) {
doc.tags.forEach(function (tag) {
emit(tag.toLowerCase(), 1);
});
}
}

In this example the map function produces documents view by tag if they
has `tags` attribute as array and `type` attribute with "post" value. Note that
:func:`emit` function could be called multiple times, so the same document
will be available by several `keys`.
In this example a key/value pair is emitted for each value in the `tags` array
of a document with a `type` of "post". Note that :func:`emit` may be called many
times for a single document, so the same document may be available by several
different keys.

Also keep in mind that each document is *sealed* to prevent situation when one
map function changes document state and the other one received a modified
Expand All @@ -77,7 +75,7 @@ each document is processed by group of map functions from all views of
related design document. This means that if you trigger index update for one
view in ddoc, all others will get updated too.

Since `1.1.0` release `map` function supports
Since `1.1.0` release `map` function supports
:ref:`CommonJS <commonjs>` modules and access to :func:`require` function.

.. _reducefun:
Expand Down Expand Up @@ -128,7 +126,7 @@ JavaScript below:

// could be replaced by _count
function(keys, values, rereduce){
if (rereduce){
if (rereduce) {
return sum(values);
} else {
return values.length;
Expand All @@ -143,11 +141,13 @@ JavaScript below:
'max': Math.max.apply(null, values),
'count': values.length,
'sumsqr': (function(){
_sumsqr = 0;
for(var idx in values){
_sumsqr += values[idx] * values[idx];
}
return _sumsqr;
var sumsqr = 0;

values.forEach(function (value) {
sumsqr += value * value;
});

return sumsqr;
})(),
}
}
Expand Down Expand Up @@ -208,7 +208,7 @@ Basic example of show function could be:
.. code-block:: javascript

function(doc, req){
if (doc){
if (doc) {
return "Hello from " + doc._id + "!";
} else {
return "Hello, world!";
Expand Down Expand Up @@ -712,7 +712,7 @@ permissions:

.. note::

The ``return`` statement used only for function, it has no impact on
The ``return`` statement used only for function, it has no impact on
the validation process.

.. seealso::
Expand Down