Add ability to support escapeChar on unparse (#631)

docs/docs.html

@@ -258,6 +258,7 @@
 {
 	quotes: false, //or array of booleans
 	quoteChar: '"',
+	escapeChar: '"',
 	delimiter: ",",
 	header: true,
 	newline: "\r\n",
@@ -293,6 +294,12 @@
 									The character used to quote fields.
 								</td>
 							</tr>
+							<tr>
+								<td><code>escapeChar</code></td>
+								<td>
+									The character used to escape <code>quoteChar</code> inside field values.
+								</td>
+							</tr>
 							<tr>
 								<td>
 									<code>delimiter</code>

papaparse.js

@@ -273,6 +273,9 @@ License: MIT
 		/** quote character */
 		var _quoteChar = '"';
 
+		/** escaped quote character, either "" or <config.escapeChar>" */
+		var _escapedQuote = _quoteChar + _quoteChar;
+
 		/** whether to skip empty lines */
 		var _skipEmptyLines = false;
 
@@ -353,6 +356,10 @@ License: MIT
 
 				_columns = _config.columns;
 			}
+
+			if (_config.escapeChar !== undefined) {
+				_escapedQuote = _config.escapeChar + _quoteChar;
+			}
 		}
 
 
@@ -439,7 +446,7 @@ License: MIT
 			if (str.constructor === Date)
 				return JSON.stringify(str).slice(1, 25);
 
-			str = str.toString().replace(quoteCharRegex, _quoteChar + _quoteChar);
+			str = str.toString().replace(quoteCharRegex, _escapedQuote);
 
 			var needsQuotes = (typeof _quotes === 'boolean' && _quotes)
 							|| (Array.isArray(_quotes) && _quotes[col])

tests/test-cases.js

@@ -1739,6 +1739,18 @@ var UNPARSE_TESTS = [
 		input: [{a: 1, b: '2'}, {}, {a: 3, d: 'd', c: 4,}],
 		config: {columns: ['a', 'b', 'c']},
 		expected: 'a,b,c\r\n1,2,\r\n\r\n3,,4'
+	},
+	{
+		description: "Use different escapeChar",
+		input: [{a: 'foo', b: '"quoted"'}],
+		config: {header: false, escapeChar: '\\'},
+		expected: 'foo,"\\"quoted\\""'
+	},
+	{
+		description: "test defeault escapeChar",
+		input: [{a: 'foo', b: '"quoted"'}],
+		config: {header: false},
+		expected: 'foo,"""quoted"""'
 	}
 ];