added get-json-with-all-fields-recursively.js

README.md

@@ -37,8 +37,8 @@ It also consolidates all relevant examples in 1 place
 
 ├── mongo
 │   ├── add-field-with-default-value.js # add a field to an existing collection with a default value
-│   └── collectionNames-and-count.js # return a list of collections in a database with the number of documents in them
+│   ├── collectionNames-and-count.js # return a list of collections in a database with the number of documents in them
-
+│   └── get-json-with-all-fields-recursively.js # returns a single object containing all different (nested) keys from all documents in a collection
 ├── typescript
 │   ├── datetime
 │   │   └── getCustomIsoString.ts # function to return a valid ISO string from a given date object

mongo/get-json-with-all-fields-recursively.js

@@ -0,0 +1,141 @@
+// This script will allow you to take an existing mongo collection
+// with many documents that are all partials of a common schema
+// and merge them together into a single instance, giving you a json schema
+
+// check whether value is an object
+function isObject(value) {
+  return value && typeof value === "object";
+}
+
+function mergeDeep(...objects) {
+  return objects.reduce((target, source) => {
+    Object.keys(source).forEach((key) => {
+      const targetKey = target[key];
+      const sourceKey = source[key];
+
+      if (Array.isArray(sourceKey)) {
+        if (!Array.isArray(targetKey)) {
+          target[key] = [];
+        }
+
+        // if array contains object
+        if (isObject(sourceKey[0])) {
+          if (!target[key][0]) {
+            target[key] = [{}];
+          }
+
+          var reduced = sourceKey.reduce((oldObject, newObject) => {
+            return mergeDeep(oldObject, newObject);
+          });
+
+          target[key] = [mergeDeep(target[key][0], reduced)];
+        } else {
+          // keep a single value
+          target[key] = sourceKey.length > 1 ? sourceKey[0] : sourceKey;
+        }
+      } else if (isObject(targetKey) && isObject(sourceKey)) {
+        target[key] = mergeDeep(targetKey, sourceKey);
+      } else {
+        target[key] = sourceKey;
+      }
+    });
+
+    return target;
+  }, {});
+}
+var dataStructure = {};
+
+db.getCollection("test")
+  .find({})
+  .forEach(function (doc) {
+    dataStructure = mergeDeep(dataStructure, doc);
+  });
+
+JSON.stringify(mergeDeep(dataStructure, { _id: "uniqueId" }), null, 2);
+
+// EXAMPLE
+
+// example input:
+/* 1 */
+// {
+//   "_id" : ObjectId("60f00f55a142cf9637dd62f9"),
+//   "complicatedArray" : [
+//       {
+//           "a" : "a"
+//       }
+//   ]
+// }
+
+// /* 2 */
+// {
+//   "_id" : ObjectId("60f00f5ea142cf9637dd630e"),
+//   "complicatedArray" : [
+//       {
+//           "b" : "b"
+//       },
+//       {
+//           "c" : "c"
+//       }
+//   ]
+// }
+
+// /* 3 */
+// {
+//   "_id" : ObjectId("60f01664a142cf9637dd654d"),
+//   "complicatedArray" : [
+//       {
+//           "b" : "b"
+//       },
+//       {
+//           "anotherNest" : {
+//               "d" : "d",
+//               "more nesting" : {
+//                   "e" : "test"
+//               }
+//           }
+//       }
+//   ]
+// }
+
+// /* 4 */
+// {
+//   "_id" : ObjectId("60f02995a142cf9637dd6b08"),
+//   "complicatedArray" : [
+//       {
+//           "anotherNest" : {
+//               "f" : "f"
+//           }
+//       }
+//   ],
+//   "simpleArray" : [
+//       0,
+//       6,
+//       7,
+//       4
+//   ],
+//   "simpleArray2" : [
+//       "string",
+//       "string2"
+//   ]
+// }
+
+// outputs
+// {
+//   "_id": "uniqueId",
+//   "complicatedArray": [
+//     {
+//       "a": "a",
+//       "b": "b",
+//       "c": "c",
+//       "anotherNest": {
+//         "d": "d",
+//         "more nesting": {
+//           "e": "test"
+//         },
+//         "f": "f"
+//       }
+//     }
+//   ],
+//   "simpleArray": 0,
+//   "simpleArray2": "string"
+// }