Add a preconditions module, and refactor errors

100% code coverage for the preconditions module.

Usage:
```
$.checkState(something === anotherthing, 'Expected something to be
anotherthing');
$.checkArgument(something < 100, 'something', 'must be less than 100');
$.checkArgumentType(something, PrivateKey, 'something'); // The third
argument is a helper to mention the name of the argument
$.checkArgumentType(something, PrivateKey); // but it's optional (will
show up as "(unknown argument)")
```

lib/errors/build.js

@@ -3,17 +3,9 @@
 var _ = require('lodash');
 var fs = require('fs');
 
-var formatMessage = function(message) {
-  message = '\'' + message + '\'';
-  for (var i = 0; i < 3; i++) {
-    message += '.replace(\'{' + i + '}\', arguments[' + i + '])';
-  }
-  return message;
-};
-
 var defineElement = function(fullName, baseClass, message) {
   return fullName + ' = function() {\n' +
-         '  this.message = ' + formatMessage(message) + ';\n' +
+         '  this.message = ' + message + ';\n' +
          '  this.stack = this.message + \'\\n\' + (new Error()).stack;\n' +
          '};\n' +
          fullName + '.prototype = Object.create(' + baseClass + '.prototype);\n' +
@@ -45,7 +37,7 @@ var traverseRoot = function(errorsDefinition) {
   var generated = '\'use strict\';\n\nvar inherits = require(\'inherits\');\n\n';
   generated += '/** AUTOGENERATED FILE. DON\'T EDIT, MODIFY "lib/errors/spec.js" INSTEAD */\n\n';
   generated += 'var bitcore = {};\n\n';
-  generated += defineElement(fullName, path, 'Internal error');
+  generated += defineElement(fullName, path, '\'Internal error\'');
   generated += childDefinitions(fullName, errorsDefinition);
   generated += 'module.exports = bitcore.Error;\n';
   return generated;

lib/errors/spec.js

@@ -1,85 +1,80 @@
+'use strict';
+
+function format(arg) {
+  return '\'' + arg
+    .replace('{0}', '\' + arguments[0] + \'')
+    .replace('{1}', '\' + arguments[1] + \'')
+    .replace('{2}', '\' + arguments[2] + \'') + '\'';
+}
+
 module.exports = [{
-  name: 'HDPrivateKey',
+    name: 'InvalidB58Char',
-  message: 'Internal Error on HDPrivateKey {0}',
+    message: format('Invalid Base58 character: {0} in {1}')
-  errors: [
+  }, {
-    {
+    name: 'InvalidB58Checksum',
-      name: 'InvalidArgument',
+    message: format('Invalid Base58 checksum for {0}')
-      message: 'Invalid Argument {0}, expected {1} but got {2}',
+  }, {
+    name: 'InvalidNetwork',
+    message: format('Invalid version for network: got {0}')
+  }, {
+    name: 'InvalidState',
+    message: format('Invalid state: {0}')
+  }, {
+    name: 'InvalidNetworkArgument',
+    message: format('Invalid network: must be "livenet" or "testnet", got {0}')
+  }, {
+    name: 'InvalidArgument',
+    message: format('Invalid Argument {0}, {1}'),
+  }, {
+    name: 'InvalidArgumentType',
+    message: format('Invalid Argument for {2}, expected {1} but got ') + '+ typeof arguments[0]',
+  }, {
+    name: 'HDPrivateKey',
+    message: format('Internal Error on HDPrivateKey {0}'),
+    errors: [{
+      name: 'InvalidDerivationArgument',
+      message: format('Invalid derivation argument {0}, expected string, or number and boolean')
+    }, {
+      name: 'InvalidEntropyArgument',
+      message: format('Invalid entropy: must be an hexa string or binary buffer, got {0}'),
       errors: [{
-        name: 'InvalidB58Char',
+        name: 'TooMuchEntropy',
-        message: 'Invalid Base58 character: {0} in {1}'
+        message: format('Invalid entropy: more than 512 bits is non standard, got "{0}"')
       }, {
-        name: 'InvalidB58Checksum',
+        name: 'NotEnoughEntropy',
-        message: 'Invalid Base58 checksum for {0}'
+        message: format('Invalid entropy: at least 128 bits needed, got "{0}"')
-      }, {
-        name: 'InvalidDerivationArgument',
-        message: 'Invalid derivation argument {0}, expected string, or number and boolean'
-      }, {
-        name: 'InvalidEntropyArgument',
-        message: 'Invalid entropy: must be an hexa string or binary buffer, got {0}',
-        errors: [{
-          name: 'TooMuchEntropy',
-          message: 'Invalid entropy: more than 512 bits is non standard, got "{0}"'
-        }, {
-          name: 'NotEnoughEntropy',
-          message: 'Invalid entropy: at least 128 bits needed, got "{0}"'
-        }]
-      }, {
-        name: 'InvalidLength',
-        message: 'Invalid length for xprivkey string in {0}'
-      }, {
-        name: 'InvalidNetwork',
-        message: 'Invalid version for network: got {0}'
-      }, {
-        name: 'InvalidNetworkArgument',
-        message: 'Invalid network: must be "livenet" or "testnet", got {0}'
-      }, {
-        name: 'InvalidPath',
-        message: 'Invalid derivation path: {0}'
-      }, {
-        name: 'UnrecognizedArgument',
-        message: 'Invalid argument: creating a HDPrivateKey requires a string, buffer, json or object, got "{0}"'
-      }]
-    }
-  ]
-}, {
-  name: 'HDPublicKey',
-  message: 'Internal Error on HDPublicKey {0}',
-  errors: [
-    {
-      name: 'InvalidArgument',
-      message: 'Invalid Argument {0}, expected {1} but got {2}',
-      errors: [{
-        name: 'ArgumentIsPrivateExtended',
-        message: 'Argument is an extended private key: {0}'
-      }, {
-        name: 'InvalidB58Char',
-        message: 'Invalid Base58 character: {0} in {1}'
-      }, {
-        name: 'InvalidB58Checksum',
-        message: 'Invalid Base58 checksum for {0}'
-      }, {
-        name: 'InvalidDerivationArgument',
-        message: 'Invalid derivation argument: got {0}'
-      }, {
-        name: 'InvalidLength',
-        message: 'Invalid length for xpubkey: got "{0}"'
-      }, {
-        name: 'InvalidNetwork',
-        message: 'Invalid network, expected a different version: got "{0}"'
-      }, {
-        name: 'InvalidNetworkArgument',
-        message: 'Expected network to be "livenet" or "testnet", got "{0}"'
-      }, {
-        name: 'InvalidPath',
-        message: 'Invalid derivation path, it should look like: "m/1/100", got "{0}"'
-      }, {
-        name: 'MustSupplyArgument',
-        message: 'Must supply an argument to create a HDPublicKey' 
-      }, {
-        name: 'UnrecognizedArgument',
-        message: 'Invalid argument for creation, must be string, json, buffer, or object'
       }]
-    }
+    }, {
-  ]
+      name: 'InvalidLength',
-}];
+      message: format('Invalid length for xprivkey string in {0}')
+    }, {
+      name: 'InvalidPath',
+      message: format('Invalid derivation path: {0}')
+    }, {
+      name: 'UnrecognizedArgument',
+      message: format('Invalid argument: creating a HDPrivateKey requires a string, buffer, json or object, got "{0}"')
+    }]
+  }, {
+    name: 'HDPublicKey',
+    message: format('Internal Error on HDPublicKey {0}'),
+    errors: [{
+      name: 'ArgumentIsPrivateExtended',
+      message: format('Argument is an extended private key: {0}')
+    }, {
+      name: 'InvalidDerivationArgument',
+      message: format('Invalid derivation argument: got {0}')
+    }, {
+      name: 'InvalidLength',
+      message: format('Invalid length for xpubkey: got "{0}"')
+    }, {
+      name: 'InvalidPath',
+      message: format('Invalid derivation path, it should look like: "m/1/100", got "{0}"')
+    }, {
+      name: 'MustSupplyArgument',
+      message: format('Must supply an argument to create a HDPublicKey')
+    }, {
+      name: 'UnrecognizedArgument',
+      message: format('Invalid argument for creation, must be string, json, buffer, or object')
+    }]
+  }
+];

lib/hdprivatekey.js

@@ -15,8 +15,8 @@ var Point = require('./crypto/point');
 var PrivateKey = require('./privatekey');
 var Random = require('./crypto/random');
 
-var bitcoreErrors = require('./errors');
+var errors = require('./errors');
-var errors = bitcoreErrors.HDPrivateKey.InvalidArgument;
+var hdErrors = errors.HDPrivateKey;
 var bufferUtil = require('./util/buffer');
 var jsUtil = require('./util/js');
 
@@ -54,7 +54,7 @@ function HDPrivateKey(arg) {
       if (_.isObject(arg)) {
         this._buildFromObject(arg);
       } else {
-        throw new errors.UnrecognizedArgument(arg);
+        throw new hdErrors.UnrecognizedArgument(arg);
       }
     }
   } else {
@@ -89,7 +89,7 @@ HDPrivateKey.prototype.derive = function(arg, hardened) {
   } else if (_.isString(arg)) {
     return this._deriveFromString(arg);
   } else {
-    throw new errors.InvalidDerivationArgument(arg);
+    throw new hdErrors.InvalidDerivationArgument(arg);
   }
 };
 
@@ -140,7 +140,7 @@ HDPrivateKey.prototype._deriveFromString = function(path) {
     return this;
   }
   if (!_.contains(HDPrivateKey.RootElementAlias, steps[0])) {
-    throw new errors.InvalidPath(path);
+    throw new hdErrors.InvalidPath(path);
   }
   steps = steps.slice(1);
 
@@ -178,7 +178,7 @@ HDPrivateKey.isValidSerialized = function(data, network) {
 HDPrivateKey.getSerializedError = function(data, network) {
   /* jshint maxcomplexity: 10 */
   if (!(_.isString(data) || bufferUtil.isBuffer(data))) {
-    return new errors.UnrecognizedArgument('Expected string or buffer');
+    return new hdErrors.UnrecognizedArgument('Expected string or buffer');
   }
   if (!Base58.validCharacters(data)) {
     return new errors.InvalidB58Char('(unknown)', data);
@@ -189,7 +189,7 @@ HDPrivateKey.getSerializedError = function(data, network) {
     return new errors.InvalidB58Checksum(data);
   }
   if (data.length !== HDPrivateKey.DataLength) {
-    return new errors.InvalidLength(data);
+    return new hdErrors.InvalidLength(data);
   }
   if (!_.isUndefined(network)) {
     var error = HDPrivateKey._validateNetwork(data, network);
@@ -265,13 +265,13 @@ HDPrivateKey.fromSeed = function(hexa, network) {
     hexa = bufferUtil.hexToBuffer(hexa);
   }
   if (!Buffer.isBuffer(hexa)) {
-    throw new errors.InvalidEntropyArgument(hexa);
+    throw new hdErrors.InvalidEntropyArgument(hexa);
   }
   if (hexa.length < MINIMUM_ENTROPY_BITS * BITS_TO_BYTES) {
-    throw new errors.InvalidEntropyArgument.NotEnoughEntropy(hexa);
+    throw new hdErrors.InvalidEntropyArgument.NotEnoughEntropy(hexa);
   }
   if (hexa.length > MAXIMUM_ENTROPY_BITS * BITS_TO_BYTES) {
-    throw new errors.InvalidEntropyArgument.TooMuchEntropy(hexa);
+    throw new hdErrors.InvalidEntropyArgument.TooMuchEntropy(hexa);
   }
   var hash = Hash.sha512hmac(hexa, new buffer.Buffer('Bitcoin seed'));
 

lib/hdpublickey.js

@@ -12,7 +12,8 @@ var Point = require('./crypto/point');
 var PublicKey = require('./publickey');
 
 var bitcoreErrors = require('./errors');
-var errors = bitcoreErrors.HDPublicKey.InvalidArgument;
+var errors = bitcoreErrors;
+var hdErrors = bitcoreErrors.HDPublicKey;
 var assert = require('assert');
 
 var jsUtil = require('./util/js');
@@ -43,7 +44,7 @@ function HDPublicKey(arg) {
       } else if (jsUtil.isValidJson(arg)) {
         return this._buildFromJson(arg);
       } else {
-        if (error instanceof errors.ArgumentIsPrivateExtended) {
+        if (error instanceof hdErrors.ArgumentIsPrivateExtended) {
           return new HDPrivateKey(arg).hdPublicKey;
         }
         throw error;
@@ -56,11 +57,11 @@ function HDPublicKey(arg) {
           return this._buildFromObject(arg);
         }
       } else {
-        throw new errors.UnrecognizedArgument(arg);
+        throw new hdErrors.UnrecognizedArgument(arg);
       }
     }
   } else {
-    throw new errors.MustSupplyArgument();
+    throw new hdErrors.MustSupplyArgument();
   }
 }
 
@@ -91,13 +92,13 @@ HDPublicKey.prototype.derive = function (arg, hardened) {
   } else if (_.isString(arg)) {
     return this._deriveFromString(arg);
   } else {
-    throw new errors.InvalidDerivationArgument(arg);
+    throw new hdErrors.InvalidDerivationArgument(arg);
   }
 };
 
 HDPublicKey.prototype._deriveWithNumber = function (index, hardened) {
   if (hardened || index >= HDPublicKey.Hardened) {
-    throw new errors.InvalidIndexCantDeriveHardened();
+    throw new hdErrors.InvalidIndexCantDeriveHardened();
   }
   var cached = HDKeyCache.get(this.xpubkey, index, hardened);
   if (cached) {
@@ -133,7 +134,7 @@ HDPublicKey.prototype._deriveFromString = function (path) {
     return this;
   }
   if (!_.contains(HDPublicKey.RootElementAlias, steps[0])) {
-    throw new errors.InvalidPath(path);
+    throw new hdErrors.InvalidPath(path);
   }
   steps = steps.slice(1);
 
@@ -172,7 +173,7 @@ HDPublicKey.getSerializedError = function (data, network) {
   /* jshint maxcomplexity: 10 */
   /* jshint maxstatements: 20 */
   if (!(_.isString(data) || bufferUtil.isBuffer(data))) {
-    return new errors.UnrecognizedArgument('expected buffer or string');
+    return new hdErrors.UnrecognizedArgument('expected buffer or string');
   }
   if (!Base58.validCharacters(data)) {
     return new errors.InvalidB58Char('(unknown)', data);
@@ -193,7 +194,7 @@ HDPublicKey.getSerializedError = function (data, network) {
   }
   network = Network.get(network) || Network.defaultNetwork;
   if (bufferUtil.integerFromBuffer(data.slice(0, 4)) === network.xprivkey) {
-    return new errors.ArgumentIsPrivateExtended();
+    return new hdErrors.ArgumentIsPrivateExtended();
   }
   return null;
 };

lib/util/preconditions.js

@@ -0,0 +1,29 @@
+'use strict';
+
+var errors = require('../errors');
+var _ = require('lodash');
+
+module.exports = {
+  checkState: function(condition, message) {
+    if (!condition) {
+      throw new errors.InvalidState(message);
+    }
+  },
+  checkArgument: function(condition, argumentName, message) {
+    if (!condition) {
+      throw new errors.InvalidArgument(argumentName, message);
+    }
+  },
+  checkArgumentType: function(argument, type, argumentName) {
+    argumentName = argumentName || '(unknown name)';
+    if (_.isString(type)) {
+      if (typeof argument !== type) {
+        throw new errors.InvalidArgumentType(argument, type, argumentName);
+      }
+    } else {
+      if (!(argument instanceof type)) {
+        throw new errors.InvalidArgumentType(argument, type.name, argumentName);
+      }
+    }
+  }
+};

test/hdprivatekey.js

@@ -5,7 +5,8 @@ var assert = require('assert');
 var should = require('chai').should();
 var expect = require('chai').expect;
 var bitcore = require('..');
-var errors = bitcore.errors.HDPrivateKey.InvalidArgument;
+var errors = bitcore.errors;
+var hdErrors = errors.HDPrivateKey;
 var buffer = require('buffer');
 var bufferUtil = bitcore.util.buffer;
 var HDPrivateKey = bitcore.HDPrivateKey;
@@ -67,7 +68,7 @@ describe('HDPrivate key interface', function() {
 
   describe('should error with a nonsensical argument', function() {
     it('like a number', function() {
-      expectFailBuilding(1, errors.UnrecognizedArgument);
+      expectFailBuilding(1, hdErrors.UnrecognizedArgument);
     });
   });
 
@@ -81,11 +82,11 @@ describe('HDPrivate key interface', function() {
   });
 
   it('fails when trying to derive with an invalid argument', function() {
-    expectDerivationFail([], errors.InvalidDerivationArgument);
+    expectDerivationFail([], hdErrors.InvalidDerivationArgument);
   });
 
   it('catches early invalid paths', function() {
-    expectDerivationFail('s', errors.InvalidPath);
+    expectDerivationFail('s', hdErrors.InvalidPath);
   });
 
   it('allows derivation of hardened keys by passing a very big number', function() {
@@ -103,14 +104,14 @@ describe('HDPrivate key interface', function() {
   it('returns InvalidArgument if invalid data is given to getSerializedError', function() {
     expect(
       HDPrivateKey.getSerializedError(1) instanceof
-      errors.UnrecognizedArgument
+      hdErrors.UnrecognizedArgument
     ).to.equal(true);
   });
 
   it('returns InvalidLength if data of invalid length is given to getSerializedError', function() {
     expect(
       HDPrivateKey.getSerializedError(Base58Check.encode(new buffer.Buffer('onestring'))) instanceof
-      errors.InvalidLength
+      hdErrors.InvalidLength
     ).to.equal(true);
   });
 
@@ -137,17 +138,17 @@ describe('HDPrivate key interface', function() {
       HDPrivateKey.fromSeed('01234567890abcdef01234567890abcdef').xprivkey.should.exist();
     });
     it('fails when argument is not a buffer or string', function() {
-      expectSeedFail(1, errors.InvalidEntropyArgument);
+      expectSeedFail(1, hdErrors.InvalidEntropyArgument);
     });
     it('fails when argument doesn\'t provide enough entropy', function() {
-      expectSeedFail('01', errors.InvalidEntropyArgument.NotEnoughEntropy);
+      expectSeedFail('01', hdErrors.InvalidEntropyArgument.NotEnoughEntropy);
     });
     it('fails when argument provides too much entropy', function() {
       var entropy = '0';
       for (var i = 0; i < 129; i++) {
         entropy += '1';
       }
-      expectSeedFail(entropy, errors.InvalidEntropyArgument.TooMuchEntropy);
+      expectSeedFail(entropy, hdErrors.InvalidEntropyArgument.TooMuchEntropy);
     });
   });
 

test/hdpublickey.js

@@ -7,7 +7,8 @@ var should = require('chai').should();
 var expect = require('chai').expect;
 var bitcore = require('..');
 var buffer = require('buffer');
-var errors = bitcore.errors.HDPublicKey.InvalidArgument;
+var errors = bitcore.errors;
+var hdErrors = bitcore.errors.HDPublicKey;
 var bufferUtil = bitcore.util.buffer;
 var HDPrivateKey = bitcore.HDPrivateKey;
 var HDPublicKey = bitcore.HDPublicKey;
@@ -65,12 +66,12 @@ describe('HDPublicKey interface', function() {
     });
 
     it('fails when user doesn\'t supply an argument', function() {
-      expectFailBuilding(null, errors.MustSupplyArgument);
+      expectFailBuilding(null, hdErrors.MustSupplyArgument);
     });
 
     it('doesn\'t recognize an invalid argument', function() {
-      expectFailBuilding(1, errors.UnrecognizedArgument);
+      expectFailBuilding(1, hdErrors.UnrecognizedArgument);
-      expectFailBuilding(true, errors.UnrecognizedArgument);
+      expectFailBuilding(true, hdErrors.UnrecognizedArgument);
     });
 
 
@@ -78,7 +79,7 @@ describe('HDPublicKey interface', function() {
       it('fails on invalid length', function() {
         expectFailBuilding(
           Base58Check.encode(new buffer.Buffer([1, 2, 3])),
-          errors.InvalidLength
+          hdErrors.InvalidLength
         );
       });
       it('fails on invalid base58 encoding', function() {
@@ -122,7 +123,7 @@ describe('HDPublicKey interface', function() {
       expect(a instanceof b).to.equal(true);
     };
     it('throws invalid argument when argument is not a string or buffer', function() {
-      compareType(HDPublicKey.getSerializedError(1), errors.UnrecognizedArgument);
+      compareType(HDPublicKey.getSerializedError(1), hdErrors.UnrecognizedArgument);
     });
     it('if a network is provided, validates that data corresponds to it', function() {
       compareType(HDPublicKey.getSerializedError(xpubkey, 'testnet'), errors.InvalidNetwork);
@@ -160,27 +161,27 @@ describe('HDPublicKey interface', function() {
     it('doesn\'t allow object arguments for derivation', function() {
       expectFail(function() {
         return new HDPublicKey(xpubkey).derive({});
-      }, errors.InvalidDerivationArgument);
+      }, hdErrors.InvalidDerivationArgument);
     });
 
     it('needs first argument for derivation', function() {
       expectFail(function() {
         return new HDPublicKey(xpubkey).derive('s');
-      }, errors.InvalidPath);
+      }, hdErrors.InvalidPath);
     });
 
     it('doesn\'t allow other parameters like m\' or M\' or "s"', function() {
       /* jshint quotmark: double */
-      expectDerivationFail("m'", errors.InvalidDerivationArgument);
+      expectDerivationFail("m'", hdErrors.InvalidDerivationArgument);
-      expectDerivationFail("M'", errors.InvalidDerivationArgument);
+      expectDerivationFail("M'", hdErrors.InvalidDerivationArgument);
-      expectDerivationFail("1", errors.InvalidDerivationArgument);
+      expectDerivationFail("1", hdErrors.InvalidDerivationArgument);
-      expectDerivationFail("S", errors.InvalidDerivationArgument);
+      expectDerivationFail("S", hdErrors.InvalidDerivationArgument);
     });
 
     it('can\'t derive hardened keys', function() {
       expectFail(function() {
         return new HDPublicKey(xpubkey).derive(HDPublicKey.Hardened + 1);
-      }, errors.InvalidDerivationArgument);
+      }, hdErrors.InvalidDerivationArgument);
     });
 
     it('should use the cache', function() {

test/util/preconditions.js

@@ -0,0 +1,61 @@
+'use strict';
+
+var errors = require('../../lib/errors');
+var $ = require('../../lib/util/preconditions');
+var PrivateKey = require('../../lib/privatekey');
+
+describe('preconditions', function() {
+
+  it('can be used to assert state', function() {
+    (function() {
+      $.checkState(false, 'testing');
+    }).should.throw(errors.InvalidState);
+  });
+  it('throws no false negative', function() {
+    (function() {
+      $.checkState(true, 'testing');
+    }).should.not.throw();
+  });
+
+  it('can be used to check an argument', function() {
+    (function() {
+      $.checkArgument(false, 'testing');
+    }).should.throw(errors.InvalidArgument);
+
+    (function() {
+      $.checkArgument(true, 'testing');
+    }).should.not.throw(errors.InvalidArgument);
+  });
+
+  it('can be used to check an argument type', function() {
+    var error;
+    try {
+      $.checkArgumentType(1, 'string', 'argumentName');
+    } catch (e) {
+      error = e;
+      e.message.should.equal('Invalid Argument for argumentName, expected string but got number');
+    }
+    error.should.exist();
+  });
+  it('has no false negatives when used to check an argument type', function() {
+    (function() {
+      $.checkArgumentType('a String', 'string', 'argumentName');
+    }).should.not.throw();
+  });
+
+  it('can be used to check an argument type for a class', function() {
+    var error;
+    try {
+      $.checkArgumentType(1, PrivateKey);
+    } catch (e) {
+      error = e;
+      e.message.should.equal('Invalid Argument for (unknown name), expected PrivateKey but got number');
+    }
+    error.should.exist();
+  });
+  it('has no false negatives when checking a type for a class', function() {
+    (function() {
+      $.checkArgumentType(new PrivateKey(), PrivateKey);
+    }).should.not.throw();
+  });
+});