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

Readme.md

@@ -44,7 +44,7 @@ console.log('  - %s cheese', program.cheese);
 
 Short flags may be passed as a single arg, for example `-abc` is equivalent to `-a -b -c`. Multi-word options such as "--template-engine" are camel-cased, becoming `program.templateEngine` etc.
 
-Note that multi-word options starting with `--no` prefix negate the boolean value of the following word. For example, `--no-sauce` sets the value of `program.sauce` to false. 
+Note that multi-word options starting with `--no` prefix negate the boolean value of the following word. For example, `--no-sauce` sets the value of `program.sauce` to false.
 
 ```js
 #!/usr/bin/env node
@@ -152,7 +152,7 @@ program
   .option('-s --size <size>', 'Pizza size', /^(large|medium|small)$/i, 'medium')
   .option('-d --drink [drink]', 'Drink', /^(coke|pepsi|izze)$/i)
   .parse(process.argv);
-  
+
 console.log(' size: %j', program.size);
 console.log(' drink: %j', program.drink);
 ```
@@ -260,7 +260,7 @@ You can enable `--harmony` option in two ways:
      -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 [marble]
      -C, --no-cheese      You do not want any cheese
 
 ```

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);
 

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-/, ''));
 };
 
 /**
@@ -392,8 +390,11 @@ 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;

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();