fixes behavior of --no-* options

A bug existed whenever a "--no"-prefixed option was defined along with
its counterpart (e.g. "--status" and "--no-status"), which caused the
corresponding boolean attribute to always be `false` when either option
was specified on the command line.

This was because the definition of a negating option would overwrite the
default value of the attribute, combined with the fact that specifying either
option would emit two events with conflicting logic.

This has been corrected in two ways:
1. During the setup of a negating option, we now check to see if the
   non-negated counterpart was already defined, in which case we don't
   set/overwrite the default value (which would be "true");
2. An option's name no longer omits its negation prefix; that is,
   "--no-cheese" is internally "no-cheese", which will distinguish it
   from "--cheese"—this will allow unique events to be registered and
   emitted, depending on which option is passed to the command, thus
   avoiding any attribute assignment collision.

Additionally, tests for negated options were added/updated to more
explicitly demonstrate the expected behavior, and a couple of relevant
examples were fixed to match their intended behavior.

Readme.md

@@ -355,13 +355,13 @@ Usage: pizza [options]
 An application for pizzas ordering
 
 Options:
-  -h, --help           output usage information
   -V, --version        output the version number
   -p, --peppers        Add peppers
   -P, --pineapple      Add pineapple
   -b, --bbq            Add bbq sauce
-  -c, --cheese <type>  Add the specified type of cheese [marble]
+  -c, --cheese [type]  Add the specified type of cheese (default: "marble")
   -C, --no-cheese      You do not want any cheese
+  -h, --help           output usage information
 ```
 
 ## Custom help

examples/pizza

@@ -12,7 +12,7 @@ program
   .option('-p, --peppers', 'Add peppers')
   .option('-P, --pineapple', 'Add pineapple')
   .option('-b, --bbq', 'Add bbq sauce')
-  .option('-c, --cheese <type>', 'Add the specified type of cheese [marble]')
+  .option('-c, --cheese [type]', 'Add the specified type of cheese', 'marble')
   .option('-C, --no-cheese', 'You do not want any cheese')
   .parse(process.argv);
 
@@ -21,9 +21,7 @@ if (program.peppers) console.log('  - peppers');
 if (program.pineapple) console.log('  - pineapple');
 if (program.bbq) console.log('  - bbq');
 
-var cheese = true === program.cheese
-  ? 'marble'
-  : program.cheese || 'no';
+var cheese = !program.cheese ? 'no' : program.cheese;
 
 console.log('  - %s cheese', cheese);
 console.log(program.args);

index.js

@@ -60,9 +60,7 @@ function Option(flags, description) {
  */
 
 Option.prototype.name = function() {
-  return this.long
-    .replace('--', '')
-    .replace('no-', '');
+  return this.long.replace(/^--/, '');
 };
 
 /**
@@ -74,7 +72,7 @@ Option.prototype.name = function() {
  */
 
 Option.prototype.attributeName = function() {
-  return camelcase(this.name());
+  return camelcase(this.name().replace(/^no-/, ''));
 };
 
 /**
@@ -335,14 +333,17 @@ Command.prototype.action = function(fn) {
  *
  * Examples:
  *
- *     // simple boolean defaulting to false
+ *     // simple boolean defaulting to undefined
  *     program.option('-p, --pepper', 'add pepper');
  *
+ *     program.pepper
+ *     // => undefined
+ *
  *     --pepper
  *     program.pepper
- *     // => Boolean
+ *     // => true
  *
- *     // simple boolean defaulting to true
+ *     // simple boolean defaulting to true (unless non-negated option is also defined)
  *     program.option('-C, --no-cheese', 'remove cheese');
  *
  *     program.cheese
@@ -392,8 +393,11 @@ Command.prototype.option = function(flags, description, fn, defaultValue) {
 
   // preassign default value only for --no-*, [optional], or <required>
   if (!option.bool || option.optional || option.required) {
-    // when --no-* we make sure default is true
-    if (!option.bool) defaultValue = true;
+    // when --no-foo we make sure default is true, unless a --foo option is already defined
+    if (!option.bool) {
+      var opts = self.opts();
+      defaultValue = name in opts ? opts[name] : true;
+    }
     // preassign only if we have a default
     if (defaultValue !== undefined) {
       self[name] = defaultValue;
@@ -424,7 +428,7 @@ Command.prototype.option = function(flags, description, fn, defaultValue) {
       }
     } else if (val !== null) {
       // reassign
-      self[name] = val;
+      self[name] = option.bool ? val : false;
     }
   });
 

test/test.options.bool.no.js

@@ -7,9 +7,25 @@ var program = require('../')
 
 program
   .version('0.0.1')
+  .option('-e, --everything', 'add all of the toppings')
   .option('-p, --pepper', 'add pepper')
+  .option('-P, --no-pepper', 'remove pepper')
   .option('-c|--no-cheese', 'remove cheese');
 
-program.parse(['node', 'test', '--no-cheese']);
-should.equal(undefined, program.pepper);
+program.parse(['node', 'test']);
+program.should.not.have.property('everything');
+program.should.not.have.property('pepper');
+program.cheese.should.be.true();
+
+program.parse(['node', 'test', '--everything']);
+program.everything.should.be.true();
+program.should.not.have.property('pepper');
+program.cheese.should.be.true();
+
+program.parse(['node', 'test', '--pepper']);
+program.pepper.should.be.true();
+program.cheese.should.be.true();
+
+program.parse(['node', 'test', '--everything', '--no-pepper', '--no-cheese']);
+program.pepper.should.be.false();
 program.cheese.should.be.false();

test/test.options.defaults.no.js

@@ -0,0 +1,23 @@
+/**
+ * Module dependencies.
+ */
+
+var program = require('../')
+  , should = require('should');
+
+program
+  .version('0.0.1')
+  .option('-p, --pepper [type]', 'add pepper', 'red')
+  .option('-P, --no-pepper', 'remove pepper');
+
+program.parse(['node', 'test']);
+program.pepper.should.equal('red');
+
+program.parse(['node', 'test', '--pepper']);
+program.pepper.should.equal('red');
+
+program.parse(['node', 'test', '--pepper', 'jalapeño']);
+program.pepper.should.equal('jalapeño');
+
+program.parse(['node', 'test', '--no-pepper']);
+program.pepper.should.be.false();