diff --git a/lib/primitives/tx.js b/lib/primitives/tx.js
index 95ef010c..6409a83f 100644
--- a/lib/primitives/tx.js
+++ b/lib/primitives/tx.js
@@ -1727,17 +1727,17 @@ TX.prototype.checkInputs = function checkInputs(view, height) {
   let total = 0;
 
   for (const {prevout} of this.inputs) {
-    let coin = view.getEntry(prevout);
+    const entry = view.getEntry(prevout);
 
-    if (!coin)
+    if (!entry)
       return [-1, 'bad-txns-inputs-missingorspent', 0];
 
-    if (coin.coinbase) {
-      if (height - coin.height < consensus.COINBASE_MATURITY)
+    if (entry.coinbase) {
+      if (height - entry.height < consensus.COINBASE_MATURITY)
         return [-1, 'bad-txns-premature-spend-of-coinbase', 0];
     }
 
-    coin = view.getOutput(prevout);
+    const coin = view.getOutput(prevout);
     assert(coin);
 
     if (coin.value < 0 || coin.value > consensus.MAX_MONEY)
@@ -2261,7 +2261,7 @@ TX.prototype.fromRaw = function fromRaw(data) {
  */
 
 TX.prototype.fromReader = function fromReader(br) {
-  if (TX.isWitness(br))
+  if (hasWitnessBytes(br))
     return this.fromWitnessReader(br);
 
   br.start();
@@ -2512,20 +2512,6 @@ TX.prototype.getWitnessSizes = function getWitnessSizes() {
   return new RawTX(base + witness, witness);
 };
 
-/**
- * Test whether data is a witness transaction.
- * @param {Buffer|BufferReader} data
- * @returns {Boolean}
- */
-
-TX.isWitness = function isWitness(br) {
-  if (br.left() < 6)
-    return false;
-
-  return br.data[br.offset + 4] === 0
-    && br.data[br.offset + 5] !== 0;
-};
-
 /**
  * Test whether an object is a TX.
  * @param {Object} obj
@@ -2540,6 +2526,14 @@ TX.isTX = function isTX(obj) {
  * Helpers
  */
 
+function hasWitnessBytes(br) {
+  if (br.left() < 6)
+    return false;
+
+  return br.data[br.offset + 4] === 0
+    && br.data[br.offset + 5] !== 0;
+}
+
 function RawTX(size, witness) {
   this.data = null;
   this.size = size;