Merge branch 'staging' of https://github.com/FreeCodeCamp/freecodecamp into greasan-translateDE

flattenUser.js

@@ -0,0 +1,94 @@
+/* eslint-disable no-process-exit */
+require('dotenv').load();
+var assign = require('lodash/object/assign'),
+    Rx = require('rx'),
+    mongodb = require('mongodb'),
+    secrets = require('../config/secrets');
+
+var MongoClient = mongodb.MongoClient;
+
+function createConnection(URI) {
+  return Rx.Observable.create(function(observer) {
+    MongoClient.connect(URI, function(err, database) {
+      if (err) {
+        return observer.onError(err);
+      }
+      observer.onNext(database);
+    });
+  });
+}
+
+function createQuery(db, collection, options, batchSize) {
+  return Rx.Observable.create(function (observer) {
+    console.log('Creating cursor...');
+    var cursor = db.collection(collection).find({}, options);
+    cursor.batchSize(batchSize || 20);
+    // Cursor.each will yield all doc from a batch in the same tick,
+    // or schedule getting next batch on nextTick
+    cursor.each(function (err, doc) {
+      if (err) {
+        return observer.onError(err);
+      }
+      if (!doc) {
+        return observer.onCompleted();
+      }
+      observer.onNext(doc);
+    });
+
+    return Rx.Disposable.create(function () {
+      console.log('Disposing cursor...');
+      cursor.close();
+    });
+  });
+}
+
+function insertMany(db, collection, users, options) {
+  return Rx.Observable.create(function(observer) {
+    db.collection(collection).insertMany(users, options, function(err) {
+      if (err) {
+        return observer.onError(err);
+      }
+      observer.onCompleted();
+    });
+  });
+}
+
+var count = 0;
+// will supply our db object
+var dbObservable = createConnection(secrets.db).shareReplay();
+dbObservable
+  .flatMap(function(db) {
+    // returns user document, n users per loop where n is the batchsize.
+    return createQuery(db, 'users', {});
+  })
+  .map(function(user) {
+    // flatten user
+    assign(user, user.portfolio, user.profile);
+    return user;
+  })
+  // batch them into arrays of twenty documents
+  .bufferWithCount(20)
+  // get bd object ready for insert
+  .withLatestFrom(dbObservable, function(users, db) {
+    return {
+      users: users,
+      db: db
+    };
+  })
+  .flatMap(function(dats) {
+    // bulk insert into new collection for loopback
+    return insertMany(dats.db, 'user', dats.users, { w: 1 });
+  })
+  // count how many times insert completes
+  .count()
+  .subscribe(
+    function(_count) {
+      count = _count * 20;
+    },
+    function(err) {
+      console.log('an error occured', err);
+    },
+    function() {
+      console.log('finished with %s documents processed', count);
+    }
+  );