feat(decode): add decodeFromReader method

package.json

@@ -33,14 +33,14 @@
   },
   "homepage": "https://github.com/dignifiedquire/pull-length-prefixed#readme",
   "dependencies": {
-    "pull-reader": "^1.2.5",
+    "pull-reader": "^1.2.8",
     "safe-buffer": "^5.0.1",
-    "varint": "^4.0.0"
+    "varint": "^4.0.1"
   },
   "devDependencies": {
-    "aegir": "^3.2.0",
+    "aegir": "^6.0.0",
     "chai": "^3.5.0",
-    "pull-pushable": "^2.0.0",
-    "pull-stream": "^3.4.2"
+    "pull-pushable": "^2.0.1",
+    "pull-stream": "^3.4.3"
   }
 }

src/decode.js

@@ -4,54 +4,61 @@ const varint = require('varint')
 const Reader = require('pull-reader')
 const Buffer = require('safe-buffer').Buffer
 
-module.exports = decode
+exports.decode = decode
+exports.decodeFromReader = decodeFromReader
 
 const MSB = 0x80
 const isEndByte = (byte) => !(byte & MSB)
 
 function decode () {
   let ended = false
   let reader = new Reader()
-  let first = true
 
   return (read) => (end, cb) => {
     reader(read)
     if (end) return reader.abort(end, cb)
     if (ended) return cb(ended)
 
-    let rawMsgSize = []
-    if (first) readByte()
-
-    // 1. Read the varint
-    function readByte () {
-      first = false
-      reader.read(1, (err, byte) => {
-        if (err) {
-          ended = err
-          return cb(ended)
-        }
-
-        rawMsgSize.push(byte)
-        if (byte && !isEndByte(byte[0])) {
-          readByte()
-        } else {
-          readMessage()
-        }
-      })
-    }
-
-    function readMessage () {
-      const msgSize = varint.decode(Buffer.concat(rawMsgSize))
+    decodeFromReader(reader, (err, msg) => {
+      if (err) {
+        ended = err
+        return cb(ended)
+      }
+
+      cb(null, msg)
+    })
+  }
+}
+
+function decodeFromReader (reader, cb) {
+  let rawMsgSize = []
+  if (rawMsgSize.length === 0) readByte()
+
+  // 1. Read the varint
+  function readByte () {
+    reader.read(1, (err, byte) => {
+      if (err) {
+        return cb(err)
+      }
+
+      rawMsgSize.push(byte)
+      if (byte && !isEndByte(byte[0])) {
+        readByte()
+      } else {
+        readMessage()
+      }
+    })
+  }
+
+  function readMessage () {
+    const msgSize = varint.decode(Buffer.concat(rawMsgSize))
+    reader.read(msgSize, (err, msg) => {
+      if (err) {
+        return cb(err)
+      }
+
       rawMsgSize = []
-      reader.read(msgSize, (err, msg) => {
-        if (err) {
-          ended = err
-          return cb(ended)
-        }
-
-        first = true
-        cb(null, msg)
-      })
-    }
+      cb(null, msg)
+    })
   }
 }

src/index.js

@@ -1,7 +1,8 @@
 'use strict'
 
 const encode = require('./encode')
-const decode = require('./decode')
+const d = require('./decode')
 
 exports.encode = encode
-exports.decode = decode
+exports.decode = d.decode
+exports.decodeFromReader = d.decodeFromReader