Merge pull request #720 from braydonf/feature/immutable-opcode

Opcode: Modify `from` methods to be static, and an instance be immutable.

lib/opcode.js

@@ -8,43 +8,42 @@ function Opcode(num) {
     return new Opcode(num);
   }
 
-  if (typeof num === 'number') {
-    this.num = num;
-  } else if (typeof num === 'string') {
-    var str = num;
-    this.num = Opcode.map[str];
-  } else if (num) {
-    var obj = num;
-    this.set(obj);
+  var value;
+
+  if (_.isNumber(num)) {
+    value = num;
+  } else if (_.isString(num)) {
+    value = Opcode.map[num];
+  } else {
+    throw new TypeError('Unrecognized num type: "' + typeof(num) + '" for Opcode');
   }
+
+  Object.defineProperty(this, 'num', {
+    configurable: false,
+    value: value
+  });
+
+  return this;
 }
 
-Opcode.prototype.set = function(obj) {
-  $.checkArgument(_.isObject(obj));
-  this.num = typeof obj.num !== 'undefined' ? obj.num : this.num;
-  return this;
+Opcode.fromNumber = function(num) {
+  $.checkArgument(_.isNumber(num));
+  return new Opcode(num);
 };
 
-Opcode.prototype.fromNumber = function(num) {
-  $.checkArgument(_.isNumber(num));
-  this.num = num;
-  return this;
+Opcode.fromString = function(str) {
+  $.checkArgument(_.isString(str));
+  var value = Opcode.map[str];
+  if (typeof value === 'undefined') {
+    throw new TypeError('Invalid opcodestr');
+  }
+  return new Opcode(value);
 };
 
 Opcode.prototype.toNumber = function() {
   return this.num;
 };
 
-Opcode.prototype.fromString = function(str) {
-  $.checkArgument(_.isString(str));
-  var num = Opcode.map[str];
-  if (typeof num === 'undefined') {
-    throw new Error('Invalid opcodestr');
-  }
-  this.num = num;
-  return this;
-};
-
 Opcode.prototype.toString = function() {
   var str = Opcode.reverseMap[this.num];
   if (typeof str === 'undefined') {
@@ -203,9 +202,7 @@ Opcode.map = {
 Opcode.reverseMap = [];
 
 for (var k in Opcode.map) {
-  if (Opcode.map.hasOwnProperty(k)) {
-    Opcode.reverseMap[Opcode.map[k]] = k;
-  }
+  Opcode.reverseMap[Opcode.map[k]] = k;
 }
 
 // Easier access to opcodes

test/opcode.js

@@ -1,7 +1,9 @@
 'use strict';
 
 var _ = require('lodash');
-var should = require('chai').should();
+var chai = require('chai');
+var should = chai.should();
+var expect = chai.expect;
 var bitcore = require('..');
 var Opcode = bitcore.Opcode;
 
@@ -26,46 +28,52 @@ describe('Opcode', function() {
 
   describe('#fromNumber', function() {
     it('should work for 0', function() {
-      Opcode().fromNumber(0).num.should.equal(0);
+      Opcode.fromNumber(0).num.should.equal(0);
     });
     it('should fail for non-number', function() {
-      Opcode().fromNumber.bind(null, 'a string').should.throw('Invalid Argument');
+      Opcode.fromNumber.bind(null, 'a string').should.throw('Invalid Argument');
     });
   });
 
   describe('#set', function() {
     it('should work for object', function() {
-      Opcode().set({
-        num: 42
-      }).num.should.equal(42);
+      Opcode(42).num.should.equal(42);
     });
-    it('should fail for non-object', function() {
-      Opcode().set.bind(null, 'non-object').should.throw('Invalid Argument');
+    it('should fail for empty-object', function() {
+      expect(function() {
+        Opcode();
+      }).to.throw(TypeError);
     });
   });
 
   describe('#toNumber', function() {
     it('should work for 0', function() {
-      Opcode().fromNumber(0).toNumber().should.equal(0);
+      Opcode.fromNumber(0).toNumber().should.equal(0);
     });
   });
 
   describe('#fromString', function() {
     it('should work for OP_0', function() {
-      Opcode().fromString('OP_0').num.should.equal(0);
+      Opcode.fromString('OP_0').num.should.equal(0);
     });
     it('should fail for invalid string', function() {
-      Opcode().fromString.bind(null, 'OP_SATOSHI').should.throw('Invalid opcodestr');
-      Opcode().fromString.bind(null, 'BANANA').should.throw('Invalid opcodestr');
+      Opcode.fromString.bind(null, 'OP_SATOSHI').should.throw('Invalid opcodestr');
+      Opcode.fromString.bind(null, 'BANANA').should.throw('Invalid opcodestr');
     });
     it('should fail for non-string', function() {
-      Opcode().fromString.bind(null, 123).should.throw('Invalid Argument');
+      Opcode.fromString.bind(null, 123).should.throw('Invalid Argument');
     });
   });
 
   describe('#toString', function() {
     it('should work for OP_0', function() {
-      Opcode().fromString('OP_0').toString().should.equal('OP_0');
+      Opcode.fromString('OP_0').toString().should.equal('OP_0');
+    });
+
+    it('should not work for non-opcode', function() {
+      expect(function(){
+        Opcode('OP_NOTACODE').toString();
+      }).to.throw('Opcode does not have a string representation');
     });
   });