[Refactor] cache default isFile functions at module level

Author: ljharb

lib/async.js

@@ -4,6 +4,16 @@ var path = require('path');
 var caller = require('./caller.js');
 var nodeModulesPaths = require('./node-modules-paths.js');
 
+var defaultIsFile = function isFile(file, cb) {
+    fs.stat(file, function (err, stat) {
+        if (!err) {
+            return cb(null, stat.isFile() || stat.isFIFO());
+        }
+        if (err.code === 'ENOENT' || err.code === 'ENOTDIR') return cb(null, false);
+        return cb(err);
+    });
+};
+
 module.exports = function resolve(x, options, callback) {
     var cb = callback;
     var opts = options || {};
@@ -18,15 +28,7 @@ module.exports = function resolve(x, options, callback) {
         });
     }
 
-    var isFile = opts.isFile || function isFile(file, cb) {
-        fs.stat(file, function (err, stat) {
-            if (!err) {
-                return cb(null, stat.isFile() || stat.isFIFO());
-            }
-            if (err.code === 'ENOENT' || err.code === 'ENOTDIR') return cb(null, false);
-            return cb(err);
-        });
-    };
+    var isFile = opts.isFile || defaultIsFile;
     var readFile = opts.readFile || fs.readFile;
 
     var extensions = opts.extensions || ['.js'];

lib/sync.js

@@ -4,20 +4,22 @@ var path = require('path');
 var caller = require('./caller.js');
 var nodeModulesPaths = require('./node-modules-paths.js');
 
+var defaultIsFile = function isFile(file) {
+    try {
+        var stat = fs.statSync(file);
+    } catch (e) {
+        if (e && (e.code === 'ENOENT' || e.code === 'ENOTDIR')) return false;
+        throw e;
+    }
+    return stat.isFile() || stat.isFIFO();
+};
+
 module.exports = function (x, options) {
     if (typeof x !== 'string') {
         throw new TypeError('Path must be a string.');
     }
     var opts = options || {};
-    var isFile = opts.isFile || function isFile(file) {
-        try {
-            var stat = fs.statSync(file);
-        } catch (e) {
-            if (e && (e.code === 'ENOENT' || e.code === 'ENOTDIR')) return false;
-            throw e;
-        }
-        return stat.isFile() || stat.isFIFO();
-    };
+    var isFile = opts.isFile || defaultIsFile;
     var readFileSync = opts.readFileSync || fs.readFileSync;
 
     var extensions = opts.extensions || ['.js'];