diff --git a/src/decoder.js b/src/decoder.js
index d0c1ed57..47827379 100644
--- a/src/decoder.js
+++ b/src/decoder.js
@@ -23,19 +23,19 @@
 */
 
 
-var Decoder={};
+let Decoder={};
 Decoder.rsDecoder = new ReedSolomonDecoder(GF256.QR_CODE_FIELD);
 
 Decoder.correctErrors=function( codewordBytes,  numDataCodewords)
 {
-	var numCodewords = codewordBytes.length;
+	let numCodewords = codewordBytes.length;
 	// First read into an array of ints
-	var codewordsInts = new Array(numCodewords);
-	for (var i = 0; i < numCodewords; i++)
+	let codewordsInts = new Array(numCodewords);
+	for (let i = 0; i < numCodewords; i++)
 	{
 		codewordsInts[i] = codewordBytes[i] & 0xFF;
 	}
-	var numECCodewords = codewordBytes.length - numDataCodewords;
+	let numECCodewords = codewordBytes.length - numDataCodewords;
 	try
 	{
 		Decoder.rsDecoder.decode(codewordsInts, numECCodewords);
@@ -48,7 +48,7 @@ Decoder.correctErrors=function( codewordBytes,  numDataCodewords)
 	}
 	// Copy back into array of bytes -- only need to worry about the bytes that were data
 	// We don't care about errors in the error-correction codewords
-	for (var i = 0; i < numDataCodewords; i++)
+	for (let i = 0; i < numDataCodewords; i++)
 	{
 		codewordBytes[i] =  codewordsInts[i];
 	}
@@ -56,40 +56,40 @@ Decoder.correctErrors=function( codewordBytes,  numDataCodewords)
 
 Decoder.decode=function(bits)
 {
-	var parser = new BitMatrixParser(bits);
-	var version = parser.readVersion();
-	var ecLevel = parser.readFormatInformation().ErrorCorrectionLevel;
+	let parser = new BitMatrixParser(bits);
+	let version = parser.readVersion();
+	let ecLevel = parser.readFormatInformation().ErrorCorrectionLevel;
 	
 	// Read codewords
-	var codewords = parser.readCodewords();
+	let codewords = parser.readCodewords();
 
 	// Separate into data blocks
-	var dataBlocks = DataBlock.getDataBlocks(codewords, version, ecLevel);
+	let dataBlocks = DataBlock.getDataBlocks(codewords, version, ecLevel);
 	
 	// Count total number of data bytes
-	var totalBytes = 0;
-	for (var i = 0; i < dataBlocks.length; i++)
+	let totalBytes = 0;
+	for (let i = 0; i < dataBlocks.length; i++)
 	{
 		totalBytes += dataBlocks[i].NumDataCodewords;
 	}
-	var resultBytes = new Array(totalBytes);
-	var resultOffset = 0;
+	let resultBytes = new Array(totalBytes);
+	let resultOffset = 0;
 	
 	// Error-correct and copy data blocks together into a stream of bytes
-	for (var j = 0; j < dataBlocks.length; j++)
+	for (let j = 0; j < dataBlocks.length; j++)
 	{
-		var dataBlock = dataBlocks[j];
-		var codewordBytes = dataBlock.Codewords;
-		var numDataCodewords = dataBlock.NumDataCodewords;
+		let dataBlock = dataBlocks[j];
+		let codewordBytes = dataBlock.Codewords;
+		let numDataCodewords = dataBlock.NumDataCodewords;
 		Decoder.correctErrors(codewordBytes, numDataCodewords);
-		for (var i = 0; i < numDataCodewords; i++)
+		for (let i = 0; i < numDataCodewords; i++)
 		{
 			resultBytes[resultOffset++] = codewordBytes[i];
 		}
 	}
 	
 	// Decode the contents of that stream of bytes
-	var reader = new QRCodeDataBlockReader(resultBytes, version.VersionNumber, ecLevel.Bits);
+	let reader = new QRCodeDataBlockReader(resultBytes, version.VersionNumber, ecLevel.Bits);
 	return reader;
 	//return DecodedBitStreamParser.decode(resultBytes, version, ecLevel);
 }