Merge pull request #163 from davemungo/DOCSP-19177-mongosh-output-in-non-json-form

DOCSP-19177 mongosh output not parsable

Author: jason-price-mongodb

source/includes/examples/ex-eval-output.rst

@@ -0,0 +1,43 @@
+.. code-block:: javascript
+
+   mongosh --quiet  --host rs0/centos1104 --port 27500 \
+           --eval "EJSON.stringify(rs.status().members.map( \
+             m => ({'id':m._id, 'name':m.name, 'stateStr':m.stateStr})));" \
+   | jq 
+
+After parsing with ``jq``, the output resembles this:
+
+.. code-block:: javascript
+   :copyable: false
+
+   [
+     {
+        "id": 0,
+        "name": "centos1104:27500",
+        "stateStr": "PRIMARY"
+     },
+     {
+        "id": 1,
+        "name": "centos1104:27502",
+        "stateStr": "SECONDARY"
+     },
+     {
+        "id": 2,
+        "name": "centos1104:27503",
+        "stateStr": "SECONDARY"
+     }
+   ]
+
+.. note::
+
+   ``EJSON`` has built in formatting options which may eliminate the
+   need for a parser like ``jq``. For example, the following code
+   produces output that is formatted the same as above. 
+
+   .. code-block:: javascript
+      :emphasize-lines: 3
+
+      mongosh --quiet  --host rs0/centos1104 --port 27500 \
+              --eval "EJSON.stringify( rs.status().members.map( \
+                ({ _id, name, stateStr }) => ({ _id, name, stateStr })), null, 2);" 
+

source/reference/compatibility.txt

@@ -154,3 +154,11 @@ in ``mongosh`` better align with the types used by the MongoDB Drivers.
    For more information on managing types, refer to the
    :manual:`schema validation overview </core/schema-validation>`.
 
+``--eval`` Behavior
+-------------------
+
+``mongosh --eval`` does not quote object keys in its ouptut. To get
+output suitable for automated parsing, use ``EJSON.stringify()``.
+
+.. include:: /includes/examples/ex-eval-output.rst
+

source/reference/options.txt

@@ -36,6 +36,11 @@ General Options
    The result of evaluating a JavaScript argument is printed to your 
    command line.
 
+   To get output suitable for automated parsing, use
+   ``EJSON.stringify()``.
+
+   .. include:: /includes/examples/ex-eval-output.rst
+
 .. option:: --help, -h
 
    Returns information on the options and use of the |mdb-shell|.