working on json2csv; already noticing a speed improvement on the tests

Author: mrodrig

lib/json-2-csv.js

@@ -13,33 +13,36 @@ var options = {}; // Initialize the options - this will be populated when the js
  * @returns {Promise}
  */
 var generateHeading = function(data) {
-    return new Promise(function (resolve, reject) {
-        if (options.KEYS) { return resolve(options.KEYS); }
-
-        var keys = _.map(_.keys(data), function (key, indx) { // for each key
-            if (_.isObject(data[key])) {
-                // if the data at the key is a document, then we retrieve the subHeading starting with an empty string heading and the doc
-                return generateSubHeading('', data[key]);
-            }
-            return key;
-        });
-
-        // Check for a consistent schema that does not require the same order:
-        // if we only have one document - then there is no possiblility of multiple schemas
-        if (keys && keys.length <= 1) {
-            return resolve(_.flatten(keys) || []);
+    if (options.KEYS) { return Promise.resolve(options.KEYS); }
+
+    var keys = _.map(data, function (document, indx) { // for each key
+        if (_.isObject(document)) {
+            // if the data at the key is a document, then we retrieve the subHeading starting with an empty string heading and the doc
+            return generateDocumentHeading('', document);
+        }
+    });
+
+    // Check for a consistent schema that does not require the same order:
+    // if we only have one document - then there is no possibility of multiple schemas
+    if (keys && keys.length <= 1) {
+        return Promise.resolve(_.flatten(keys) || []);
+    }
+    // else - multiple documents - ensure only one schema (regardless of field ordering)
+    var firstDocSchema = _.flatten(keys[0]),
+        schemaDifferences = 0;
+
+    _.each(keys, function (keyList) {
+        // If there is a difference between the schemas, increment the counter of schema inconsistencies
+        var diff = _.difference(firstDocSchema, _.flatten(keyList));
+        if (!_.isEqual(diff, [])) {
+            schemaDifferences++;
         }
-        // else - multiple documents - ensure only one schema (regardless of field ordering)
-        var firstDocSchema = _.flatten(keys[0]);
-        _.each(keys, function (keyList) {
-            // If there is a difference between the schemas, throw the inconsistent schema error
-            var diff = _.difference(firstDocSchema, _.flatten(keyList));
-            if (!_.isEqual(diff, [])) {
-                return reject(new Error(constants.Errors.json2csv.notSameSchema));
-            }
-        });
-        return resolve(_.flatten(keys[0]));
     });
+
+    // If there are schema inconsistencies, throw a schema not the same error
+    if (schemaDifferences) { return Promise.reject(new Error(constants.Errors.json2csv.notSameSchema)); }
+
+    return Promise.resolve(_.flatten(keys[0]));
 };
 
 /**
@@ -48,21 +51,22 @@ var generateHeading = function(data) {
  * @param data
  * @returns {Array}
  */
-var generateSubHeading = function(heading, data) {
-    var subKeys, // retrieve the keys from the current document
-        newKey = ''; // temporary variable to aid in determining the heading - used to generate the 'nested' headings
+var generateDocumentHeading = function(heading, data) {
+    var keyName = ''; // temporary variable to aid in determining the heading - used to generate the 'nested' headings
 
-    subKeys = _.map(_.keys(data), function (subKey) {
+    var documentKeys = _.map(_.keys(data), function (currentKey) {
         // If the given heading is empty, then we set the heading to be the subKey, otherwise set it as a nested heading w/ a dot
-        newKey = heading === '' ? subKey : heading + '.' + subKey;
-        if (_.isObject(data[subKey]) && !_.isNull(data[subKey]) && _.isUndefined(data[subKey].length) && _.keys(data[subKey]).length > 0) { // If we have another nested document
-            return generateSubHeading(newKey, data[subKey]); // Recur on the sub-document to retrieve the full key name
-        } else {
-            return newKey; // Set the key name since we don't have a sub document
+        keyName = heading ? heading + '.' + currentKey : currentKey;
+
+        // If we have another nested document, recur on the sub-document to retrieve the full key name
+        if (_.isObject(data[currentKey]) && !_.isNull(data[currentKey]) && _.isUndefined(data[currentKey].length) && _.keys(data[currentKey]).length) {
+            return generateDocumentHeading(keyName, data[currentKey]);
         }
+        // Otherwise return this key name since we don't have a sub document
+        return keyName;
     });
 
-    return subKeys; // Return the headings joined by our field delimiter
+    return documentKeys; // Return the headings joined by our field delimiter
 };
 
 /**
@@ -83,7 +87,7 @@ var convertData = function (data, keys) {
             output.push(convertData(data[pathPrefix], [pathRemainder]));
         } else if (keys.indexOf(key) > -1) { // If the keys contain the current key, then process the data
             value = data[key]; // Set the current data that we are looking at
-            convertField(value, output);
+            output.push(convertField(value, output));
         }
     });
     return output; // Return the data joined by our field delimiter
@@ -94,17 +98,15 @@ var convertData = function (data, keys) {
  * @param value
  * @param output
  */
-var convertField = function (value, output) {
+var convertField = function (value) {
     if (_.isArray(value)) { // We have an array of values
-        output.push(options.DELIMITER.WRAP + '[' + value.join(options.DELIMITER.ARRAY) + ']' + options.DELIMITER.WRAP);
+        return options.DELIMITER.WRAP + '[' + value.join(options.DELIMITER.ARRAY) + ']' + options.DELIMITER.WRAP;
     } else if (_.isDate(value)) { // If we have a date
-        output.push(value.toString());
+        return options.DELIMITER.WRAP + value.toString() + options.DELIMITER.WRAP;
     } else if (_.isObject(value)) { // If we have an object
-        output.push(convertData(value, _.keys(value))); // Push the recursively generated CSV
-    } else {
-        value = value ? value.toString() : '';
-        output.push(options.DELIMITER.WRAP + value + options.DELIMITER.WRAP); // Otherwise push the current value
+        return options.DELIMITER.WRAP + convertData(value, _.keys(value)) + options.DELIMITER.WRAP; // Push the recursively generated CSV
     }
+    return options.DELIMITER.WRAP + (value ? value.toString() : '') + options.DELIMITER.WRAP; // Otherwise push the current value
 };
 
 /**