Add —-orphans to show modules that no one is depending on

README.md

@@ -115,7 +115,19 @@ madge('path/to/app.js').then((res) => {
 const madge = require('madge');
 
 madge('path/to/app.js').then((res) => {
-	console.log(res.depends());
+	console.log(res.depends('lib/log.js'));
+});
+```
+
+#### .orphans()
+
+> Return a `Array` of all modules that no one is depending on.
+
+```javascript
+const madge = require('madge');
+
+madge('path/to/app.js').then((res) => {
+	console.log(res.orphans());
 });
 ```
 
@@ -226,13 +238,13 @@ $ madge --circular path/src/app.js
 > Show modules that depends on a given module
 
 ```sh
-$ madge --depends 'wheels' path/src/app.js
+$ madge --depends wheels.js path/src/app.js
 ```
 
 > Excluding modules
 
 ```sh
-$ madge --exclude '^(foo|bar)$' path/src/app.js
+$ madge --exclude '^(foo|bar)\.js$' path/src/app.js
 ```
 
 > Save graph as a SVG image (graphviz required)

bin/cli.js

@@ -21,6 +21,7 @@ program
 	.option('-j, --json', 'output as JSON')
 	.option('-i, --image <file>', 'write graph to file as an image')
 	.option('-l, --layout <name>', 'layout engine to use for graph (dot/neato/fdp/sfdp/twopi/circo)')
+	.option('--orphans', 'show modules that no one is depending on')
 	.option('--dot', 'show graph using the DOT language')
 	.option('--extensions <list>', 'comma separated string of valid file extensions')
 	.option('--require-config <file>', 'path to RequireJS config')
@@ -164,6 +165,14 @@ new Promise((resolve, reject) => {
 		return res;
 	}
 
+	if (program.orphans) {
+		output.modules(res.orphans(), {
+			json: program.json
+		});
+
+		return res;
+	}
+
 	if (program.circular) {
 		const circular = res.circular();
 

lib/api.js

@@ -103,6 +103,28 @@ class Madge {
 			.filter((dep) => tree[dep].indexOf(id) >= 0);
 	}
 
+	/**
+	* Return a list of modules that no one is depending on.
+	* @api public
+	* @return {Array}
+	*/
+	orphans() {
+		const tree = this.obj();
+		const map = {};
+
+		Object
+			.keys(tree)
+			.forEach((dep) => {
+				tree[dep].forEach((id) => {
+					map[id] = true;
+				});
+			});
+
+		return Object
+			.keys(tree)
+			.filter((dep) => !map[dep]);
+	}
+
 	/**
 	 * Return the module dependency graph as DOT output.
 	 * @api public

test/api.js

@@ -207,6 +207,15 @@ describe('API', () => {
 		});
 	});
 
+	describe('orphans()', () => {
+		it('returns modules that no one is depending on', (done) => {
+			madge(__dirname + '/cjs/normal').then((res) => {
+				res.orphans().should.eql(['a.js']);
+				done();
+			}).catch(done);
+		});
+	});
+
 	describe('image()', () => {
 		let imagePath;