use system binary if possible

index.js

@@ -6,6 +6,7 @@ var binCheck = lazyReq('bin-check');
 var binVersionCheck = lazyReq('bin-version-check');
 var Download = lazyReq('download');
 var osFilterObj = lazyReq('os-filter-obj');
+var which = require('which');
 
 /**
  * Initialize a new `BinWrapper`
@@ -109,6 +110,12 @@ BinWrapper.prototype.version = function (range) {
  */
 
 BinWrapper.prototype.path = function () {
+	var systemBin = which.sync(this.use(), {nothrow: true})
+
+	if (systemBin) {
+		return systemBin;
+	}
+
 	return path.join(this.dest(), this.use());
 };
 

package.json

@@ -30,7 +30,8 @@
     "download": "^4.0.0",
     "each-async": "^1.1.1",
     "lazy-req": "^1.0.0",
-    "os-filter-obj": "^1.0.0"
+    "os-filter-obj": "^1.0.0",
+    "which": "^1.3.0"
   },
   "devDependencies": {
     "ava": "*",

readme.md

@@ -35,6 +35,7 @@ Get the path to your binary with `bin.path()`:
 console.log(bin.path()); // => path/to/vendor/gifsicle
 ```
 
+> if you have the requested binary installed globally, this one will be used instead (if everything works)
 
 ## API
 

test.js

@@ -121,3 +121,13 @@ test('error if no binary is found and no source is provided', t => {
 
 	t.throws(pify(bin.run.bind(bin))(), 'No binary found matching your system. It\'s probably not supported.');
 });
+
+test('can use a system binary if found in PATH', async t => {
+	const bin = new Fn()
+		.dest(tempfile())
+		.use(process.platform === 'win32' ? 'node.exe' : 'node');
+
+	await pify(bin.run.bind(bin))();
+
+	t.true(await pathExists(bin.path()));
+});