Assume a string parameter to implies is name of boolean option. (#1854)

examples/options-implies.js

@@ -3,7 +3,6 @@
 const { Command, Option } = require('../'); // include commander in git clone of commander repo
 const program = new Command();
 
-// You can use .conflicts() with a single string, which is the camel-case name of the conflicting option.
 program
   .addOption(new Option('--quiet').implies({ logLevel: 'off' }))
   .addOption(new Option('--log-level <level>').choices(['info', 'warning', 'error', 'off']).default('info'))

lib/option.js

@@ -99,7 +99,12 @@ class Option {
    * @return {Option}
    */
   implies(impliedOptionValues) {
-    this.implied = Object.assign(this.implied || {}, impliedOptionValues);
+    let newImplied = impliedOptionValues;
+    if (typeof impliedOptionValues === 'string') {
+      // string is not documented, but easy mistake and we can do what user probably intended.
+      newImplied = { [impliedOptionValues]: true };
+    }
+    this.implied = Object.assign(this.implied || {}, newImplied);
     return this;
   }
 

tests/options.implies.test.js

@@ -201,3 +201,14 @@ test('when implied option has custom processing then custom processing not calle
   expect(program.opts().bar).toEqual(true);
   expect(called).toEqual(false);
 });
+
+test('when passed string then treat as boolean', () => {
+  // Do something sensible instead of something silly if user passes just name of option.
+  // https://github.com/tj/commander.js/issues/1852
+  const program = new Command();
+  program
+    .addOption(new Option('--foo').implies('bar'))
+    .option('-b, --bar', 'description');
+  program.parse(['--foo'], { from: 'user' });
+  expect(program.opts().bar).toEqual(true);
+});