Return all fields when not setting fields param

Fixes #104

lib/json2csv.js

@@ -3,6 +3,8 @@
  */
 var os = require('os');
 var lodashGet = require('lodash.get');
+var lodashFlatten = require('lodash.flatten');
+var lodashUniq = require('lodash.uniq');
 var flatten = require('flat');
 
 /**
@@ -17,8 +19,8 @@ var flatten = require('flat');
  */
 module.exports = function (params, callback) {
   var hasCallback = typeof callback === 'function';
-
   var err;
+
   try {
     checkParams(params);
   } catch (err) {
@@ -30,8 +32,10 @@ module.exports = function (params, callback) {
       throw err;
     }
   }
+
   var titles = createColumnTitles(params);
   var csv = createColumnContent(params, titles);
+
   if (hasCallback) {
     return process.nextTick(function () {
       callback(null, csv);
@@ -67,7 +71,16 @@ function checkParams(params) {
   if (!params.fields && (params.data.length === 0 || typeof params.data[0] !== 'object')) {
     throw new Error('params should include "fields" and/or non-empty "data" array of objects');
   }
-  params.fields = params.fields || Object.keys(params.data[0]);
+
+  if (!params.fields) {
+    var dataFields = params.data.map(function (item) {
+      return Object.keys(item);
+    });
+
+    dataFields = lodashFlatten(dataFields);
+    params.fields = lodashUniq(dataFields);
+    debugger;
+  }
 
 
   //#check fieldNames

package.json

@@ -34,7 +34,9 @@
     "commander": "^2.8.1",
     "debug": "^2.2.0",
     "flat": "^2.0.0",
+    "lodash.flatten": "^4.2.0",
     "lodash.get": "^4.3.0",
+    "lodash.uniq": "^4.3.0",
     "path-is-absolute": "^1.0.0"
   },
   "devDependencies": {

test/fixtures/csv/default.csv

@@ -1,5 +1,5 @@
-"carModel","price","color"
-"Audi",0,"blue"
-"BMW",15000,"red"
-"Mercedes",20000,"yellow"
-"Porsche",30000,"green"
+"carModel","price","color","transmission"
+"Audi",0,"blue",
+"BMW",15000,"red","manual"
+"Mercedes",20000,"yellow",
+"Porsche",30000,"green",

test/fixtures/json/default.json

@@ -1,6 +1,6 @@
 [
   { "carModel": "Audi",      "price": 0,  "color": "blue" },
-  { "carModel": "BMW",       "price": 15000,  "color": "red" },
+  { "carModel": "BMW",       "price": 15000,  "color": "red", "transmission": "manual" },
   { "carModel": "Mercedes",  "price": 20000,  "color": "yellow" },
   { "carModel": "Porsche",   "price": 30000,  "color": "green" }
 ]

test/index.js

@@ -74,7 +74,7 @@ async.parallel(loadFixtures(csvFixtures), function (err) {
   test('should parse json to csv', function (t) {
     json2csv({
       data: jsonDefault,
-      fields: ['carModel', 'price', 'color']
+      fields: ['carModel', 'price', 'color', 'transmission']
     }, function (error, csv) {
       t.error(error);
       t.equal(csv, csvFixtures.default);