also return length from decode

README.md

@@ -6,7 +6,7 @@ encode whole numbers to an array of [protobuf-style varint bytes](https://develo
 var varint = require('varint')
 
 var bytes = varint.encode(300) // === [0xAC, 0x02]
-varint.decode(bytes) // 300
+varint.decode(bytes) // [300, 2]
 ```
 
 ## api
@@ -18,9 +18,9 @@ varint.decode(bytes) // 300
 encodes `num` into either the array given by `offset` or a new array at `offset`
 and returns that array filled with integers.
 
-### varint.decode(data[, offset=0]) -> number
+### varint.decode(data[, offset=0]) -> [number, length]
 
-decodes `data`, which can be either a buffer or array of integers, from position `offset` or default 0 and returns the decoded integer
+decodes `data`, which can be either a buffer or array of integers, from position `offset` or default 0 and returns an array containing `[number, length]` where number is the original integer and length is the amount of bytes that were consumed in order to decode the number
 
 # License
 

decode.js

@@ -7,15 +7,16 @@ function read(buf, offset) {
   var res    = 0
     , offset = offset || 0
     , shift  = 0
+    , counter = offset
     , b
   
   do {
-    b = buf[offset++]
+    b = buf[counter++]
     res += shift < 28
       ? (b & REST) << shift
       : (b & REST) * Math.pow(2, shift)
     shift += 7
   } while (b >= MSB)
   
-  return res
+  return [res, counter - offset]
 }

test.js

@@ -9,7 +9,8 @@ test('fuzz test', function(assert) {
     expect = randint(0x7FFFFFFF)
     encoded = varint.encode(expect)
     var data = varint.decode(encoded)
-    assert.equal(expect, data, 'fuzz test: '+expect.toString())
+    assert.equal(expect, data[0], 'fuzz test: '+expect.toString())
+    assert.equal(data[1], encoded.length)
   }
 
   assert.end()
@@ -20,7 +21,8 @@ test('test single byte works as expected', function(assert) {
   buf[0] = 172
   buf[1] = 2
   var data = varint.decode(buf)
-  assert.equal(data, 300, 'should equal 300')
+  assert.equal(data[0], 300, 'should equal 300')
+  assert.equal(data[1], 2)
   assert.end()
 })
 
@@ -37,7 +39,8 @@ test('test decode single bytes', function(assert) {
   var buf = new Uint8Array(1)
   buf[0] = expected
   var data = varint.decode(buf)
-  assert.equal(data, expected)
+  assert.equal(data[0], expected)
+  assert.equal(data[1], 1)
   assert.end()
 })
 
@@ -47,7 +50,8 @@ test('test decode multiple bytes with zero', function(assert) {
   buf[0] = 128
   buf[1] = expected
   var data = varint.decode(buf)
-  assert.equal(data, expected << 7)
+  assert.equal(data[0], expected << 7)
+  assert.equal(data[1], 2)
   assert.end()
 })