From 265e09c67a16bea4e21ae9565defc6e913a2a0ea Mon Sep 17 00:00:00 2001
From: Jonathan Grimes <jsg2021@users.noreply.github.com>
Date: Mon, 4 Feb 2019 02:50:56 -0600
Subject: [PATCH] Ensure data is correctly parsed with header: true (#621)

Fixes #619
---
 papaparse.js        | 48 +++++++++++++++++++++++++++++++--------------
 tests/test-cases.js | 33 +++++++++++++++++++++++++++++++
 2 files changed, 66 insertions(+), 15 deletions(-)

diff --git a/papaparse.js b/papaparse.js
index e0ddca9..5ed703e 100755
--- a/papaparse.js
+++ b/papaparse.js
@@ -1125,18 +1125,25 @@ License: MIT
 		{
 			if (!_results)
 				return;
-			for (var i = 0; needsHeaderRow() && i < _results.data.length; i++)
-				for (var j = 0; j < _results.data[i].length; j++)
-				{
-					var header = _results.data[i][j];
 
-					if (isFunction(_config.transformHeader)) {
-						header = _config.transformHeader(header);
-					}
+			function addHeder(header)
+			{
+				if (isFunction(_config.transformHeader))
+					header = _config.transformHeader(header);
 
-					_fields.push(header);
-				}
-			_results.data.splice(0, 1);
+				_fields.push(header);
+			}
+
+			if (Array.isArray(_results.data[0]))
+			{
+				for (var i = 0; needsHeaderRow() && i < _results.data.length; i++)
+					_results.data[i].forEach(addHeder);
+
+				_results.data.splice(0, 1);
+			}
+			// if _results.data[0] is not an array, we are in a step where _results.data is the row.
+			else
+				_results.data.forEach(addHeder);
 		}
 
 		function shouldApplyDynamicTyping(field) {
@@ -1170,15 +1177,15 @@ License: MIT
 			if (!_results || (!_config.header && !_config.dynamicTyping && !_config.transform))
 				return _results;
 
-			for (var i = 0; i < _results.data.length; i++)
+			function processRow(rowSource, i)
 			{
 				var row = _config.header ? {} : [];
 
 				var j;
-				for (j = 0; j < _results.data[i].length; j++)
+				for (j = 0; j < rowSource.length; j++)
 				{
 					var field = j;
-					var value = _results.data[i][j];
+					var value = rowSource[j];
 
 					if (_config.header)
 						field = j >= _fields.length ? '__parsed_extra' : _fields[j];
@@ -1197,7 +1204,6 @@ License: MIT
 						row[field] = value;
 				}
 
-				_results.data[i] = row;
 
 				if (_config.header)
 				{
@@ -1206,12 +1212,24 @@ License: MIT
 					else if (j < _fields.length)
 						addError('FieldMismatch', 'TooFewFields', 'Too few fields: expected ' + _fields.length + ' fields but parsed ' + j, _rowCounter + i);
 				}
+
+				return row;
+			}
+
+			var incrementBy = 1;
+			if (!_results.data[0] || Array.isArray(_results.data[0]))
+			{
+				_results.data = _results.data.map(processRow);
+				incrementBy = _results.data.length;
 			}
+			else
+				_results.data = processRow(_results.data, 0);
+
 
 			if (_config.header && _results.meta)
 				_results.meta.fields = _fields;
 
-			_rowCounter += _results.data.length;
+			_rowCounter += incrementBy;
 			return _results;
 		}
 
diff --git a/tests/test-cases.js b/tests/test-cases.js
index 0b34f0d..b0610dd 100644
--- a/tests/test-cases.js
+++ b/tests/test-cases.js
@@ -1804,6 +1804,39 @@ var CUSTOM_TESTS = [
 			});
 		}
 	},
+	{
+		description: "Data is correctly parsed with steps (headers)",
+		expected: [{One: 'A', Two: 'b', Three: 'c'}, {One: 'd', Two: 'E', Three: 'f'}],
+		run: function(callback) {
+			var data = [];
+			Papa.parse('One,Two,Three\nA,b,c\nd,E,f', {
+				header: true,
+				step: function(results) {
+					data.push(results.data);
+				},
+				complete: function() {
+					callback(data);
+				}
+			});
+		}
+	},
+	{
+		description: "Data is correctly parsed with steps and worker (headers)",
+		expected: [{One: 'A', Two: 'b', Three: 'c'}, {One: 'd', Two: 'E', Three: 'f'}],
+		run: function(callback) {
+			var data = [];
+			Papa.parse('One,Two,Three\nA,b,c\nd,E,f', {
+				header: true,
+				worker: true,
+				step: function(results) {
+					data.push(results.data);
+				},
+				complete: function() {
+					callback(data);
+				}
+			});
+		}
+	},
 	{
 		description: "Data is correctly parsed with steps and worker",
 		expected: [['A', 'b', 'c'], ['d', 'E', 'f']],