[Fix] handle non-Uint8Arrays in node < 3

Author: ChALkeR

.eslintrc

@@ -7,4 +7,9 @@
 		"Uint8Array": "readonly",
 		"Uint16Array": "readonly",
 	},
+
+	"rules": {
+		"complexity": "off",
+		"max-lines-per-function": "off",
+	},
 }

index.js

@@ -6,8 +6,8 @@ var isArray = require('isarray');
 var useUint8Array = typeof Uint8Array !== 'undefined';
 var useArrayBuffer = typeof ArrayBuffer !== 'undefined'
 	&& typeof Uint8Array !== 'undefined'
-	&& ArrayBuffer.isView
-	&& (Buffer.prototype instanceof Uint8Array || Buffer.TYPED_ARRAY_SUPPORT);
+	&& ArrayBuffer.isView;
+var useFromArrayBuffer = useArrayBuffer && (Buffer.prototype instanceof Uint8Array || Buffer.TYPED_ARRAY_SUPPORT);
 
 module.exports = function toBuffer(data, encoding) {
 	/*
@@ -18,7 +18,6 @@ module.exports = function toBuffer(data, encoding) {
 		return data;
 	}
 
-	// Convert strings to Buffer
 	if (typeof data === 'string') {
 		return Buffer.from(data, encoding);
 	}
@@ -33,13 +32,28 @@ module.exports = function toBuffer(data, encoding) {
 			return Buffer.alloc(0);
 		}
 
-		var res = Buffer.from(data.buffer, data.byteOffset, data.byteLength);
+		// When Buffer is based on Uint8Array, we can just construct it from ArrayBuffer
+		if (useFromArrayBuffer) {
+			var res = Buffer.from(data.buffer, data.byteOffset, data.byteLength);
+			/*
+			 * Recheck result size, as offset/length doesn't work on Node.js <5.10
+			 * We just go to Uint8Array case if this fails
+			 */
+			if (res.byteLength === data.byteLength) {
+				return res;
+			}
+		}
+
+		// Convert to Uint8Array bytes and then to Buffer
+		var uint8 = data instanceof Uint8Array ? data : new Uint8Array(data.buffer, data.byteOffset, data.byteLength);
+		var result = Buffer.from(uint8);
+
 		/*
-		 * Recheck result size, as offset/length doesn't work on Node.js <5.10
-		 * We just go to Uint8Array case if this fails
+		 * Let's recheck that conversion succeeded
+		 * We have .length but not .byteLength when useFromArrayBuffer is false
 		 */
-		if (res.byteLength === data.byteLength) {
-			return res;
+		if (result.length === data.byteLength) {
+			return result;
 		}
 	}
 

test/index.js

@@ -46,30 +46,26 @@ test('other input throws', function (t) {
 });
 
 test('handle all TA types', function (t) {
-	if (ArrayBuffer.isView && (Buffer.prototype instanceof Uint8Array || Buffer.TYPED_ARRAY_SUPPORT)) {
-		forEach(availableTypedArrays, function (type) {
-			var TA = global[type];
-			if (!(type in fixtures)) {
-				t.fail('No fixtures for ' + type);
-				return;
-			}
+	forEach(availableTypedArrays, function (type) {
+		var TA = global[type];
+		if (!(type in fixtures)) {
+			t.fail('No fixtures for ' + type);
+			return;
+		}
 
-			var input = fixtures[type].input;
-			if (typeof input[0] === 'string') {
-				for (var i = 0; i < input.length; i++) {
-					input[i] = BigInt(input[i]);
-				}
+		var input = fixtures[type].input;
+		if (typeof input[0] === 'string') {
+			for (var i = 0; i < input.length; i++) {
+				input[i] = BigInt(input[i]);
 			}
+		}
 
-			t.deepEqual(
-				toBuffer(new TA(input)),
-				new Buffer(fixtures[type].output),
-				type + ' should be converted to Buffer correctly'
-			);
-		});
-	} else {
-		t.skip('ArrayBuffer.isView and/or TypedArray not fully supported');
-	}
+		t.deepEqual(
+			toBuffer(new TA(input)),
+			new Buffer(fixtures[type].output),
+			type + ' should be converted to Buffer correctly'
+		);
+	});
 
 	t.end();
 });