Allow transforming header columns

papaparse.js

@@ -1151,6 +1151,10 @@ if (!Array.isArray)
 						header = header.trim();
 					}
 
+					if (isFunction(_config.transformHeader)) {
+						header = _config.transformHeader(header);
+					}
+
 					_fields.push(header);
 				}
 			_results.data.splice(0, 1);

tests/test-cases.js

@@ -733,6 +733,15 @@ var PARSE_TESTS = [
 			errors: []
 		}
 	},
+	{
+		description: "Header rows transformed",
+		input: 'A,B,C\r\na,b,c',
+		config: { header: true, transformHeader: function(header) { return header.toLowerCase(); } },
+		expected: {
+			data: [{"a": "a", "b": "b", "c": "c"}],
+			errors: []
+		}
+	},
 	{
 		description: "Line ends with quoted field, first field of next line is empty using headers",
 		input: 'a,b,"c"\r\nd,e,"f"\r\n,"h","i"\r\n,"k","l"',