diff --git a/lib/bcoin/script.js b/lib/bcoin/script.js
index 1617a245..88e143db 100644
--- a/lib/bcoin/script.js
+++ b/lib/bcoin/script.js
@@ -1237,10 +1237,10 @@ Script.checkPush = function checkPush(value, flags) {
     return pushdata.opcode == null && pushdata.len === value.length;
 
   if (value.length <= 255)
-    return pushdata.opcode === 'pushdata1';
+    return pushdata.opcode === constants.opcodes.pushdata1;
 
   if (value.length <= 65535)
-    return pushdata.opcode === 'pushdata2';
+    return pushdata.opcode === constants.opcodes.pushdata2;
 
   return true;
 };
@@ -2596,7 +2596,7 @@ Script.sign = function sign(msg, key, type) {
 Script.decode = function decode(buf) {
   var code = [];
   var off = 0;
-  var b, opcode, len;
+  var b, len;
 
   assert(Buffer.isBuffer(buf));
 
@@ -2637,48 +2637,46 @@ Script.decode = function decode(buf) {
       continue;
     }
 
-    opcode = constants.opcodesByVal[b];
-
     if (off >= buf.length) {
-      code.push(opcode || b);
+      code.push(constants.opcodesByVal[b] || b);
       continue;
     }
 
-    if (opcode === 'pushdata1') {
+    if (b === constants.opcodes.pushdata1) {
       len = buf[off];
       off += 1;
       code.push(buf.slice(off, off + len));
       off += len;
       if (len <= 0x4b || off > buf.length) {
         utils.hidden(code[code.length - 1], 'pushdata', {
-          opcode: opcode,
+          opcode: b,
           len: len
         });
       }
-    } else if (opcode === 'pushdata2') {
+    } else if (b === constants.opcodes.pushdata2) {
       len = utils.readU16(buf, off);
       off += 2;
       code.push(buf.slice(off, off + len));
       off += len;
       if (len <= 0xff || off > buf.length) {
         utils.hidden(code[code.length - 1], 'pushdata', {
-          opcode: opcode,
+          opcode: b,
           len: len
         });
       }
-    } else if (opcode === 'pushdata4') {
+    } else if (b === constants.opcodes.pushdata4) {
       len = utils.readU32(buf, off);
       off += 4;
       code.push(buf.slice(off, off + len));
       off += len;
       if (len <= 0xffff || off > buf.length) {
         utils.hidden(code[code.length - 1], 'pushdata', {
-          opcode: opcode,
+          opcode: b,
           len: len
         });
       }
     } else {
-      code.push(opcode || b);
+      code.push(constants.opcodesByVal[b] || b);
     }
   }
 
@@ -2704,15 +2702,15 @@ Script.encode = function encode(code) {
         if (op.pushdata.opcode === null) {
           p.writeU8(op.pushdata.len);
           p.writeBytes(op);
-        } else if (op.pushdata.opcode === 'pushdata1') {
+        } else if (op.pushdata.opcode === opcodes.pushdata1) {
           p.writeU8(opcodes.pushdata1);
           p.writeU8(op.pushdata.len);
           p.writeBytes(op);
-        } else if (op.pushdata.opcode === 'pushdata2') {
+        } else if (op.pushdata.opcode === opcodes.pushdata2) {
           p.writeU8(opcodes.pushdata2);
           p.writeU16(op.pushdata.len);
           p.writeBytes(op);
-        } else if (op.pushdata.opcode === 'pushdata4') {
+        } else if (op.pushdata.opcode === opcodes.pushdata4) {
           p.writeU8(opcodes.pushdata4);
           p.writeU32(op.pushdata.len);
           p.writeBytes(op);