From e19e946cb36127b1bdd5f590cb07e1108695fbbf Mon Sep 17 00:00:00 2001
From: Tony Valderrama <tony.valderrama@outlook.com>
Date: Mon, 21 Aug 2017 11:36:30 -0700
Subject: [PATCH 01/20] Pull resolve.sync code directly into default_resolver.
 (incomplete)

---
 packages/jest-resolve/src/default_resolver.js | 92 +++++++++++++++++++
 1 file changed, 92 insertions(+)

diff --git a/packages/jest-resolve/src/default_resolver.js b/packages/jest-resolve/src/default_resolver.js
index a4799d07aeb1..338e87f86a72 100644
--- a/packages/jest-resolve/src/default_resolver.js
+++ b/packages/jest-resolve/src/default_resolver.js
@@ -33,3 +33,95 @@ function defaultResolver(path: Path, options: ResolverOptions) {
 }
 
 module.exports = defaultResolver;
+
+/**
+ * resolve logic, taken directly from resolve.sync
+ */
+
+var core = require('./core');
+var fs = require('fs');
+var path = require('path');
+var caller = require('./caller.js');
+var nodeModulesPaths = require('./node-modules-paths.js');
+
+function resolveSync(x, options) {
+  var opts = options || {};
+  var isFile = opts.isFile || function (file) {
+    try {
+      var stat = fs.statSync(file);
+    } catch (e) {
+      if (e && e.code === 'ENOENT') return false;
+      throw e;
+    }
+    return stat.isFile() || stat.isFIFO();
+  };
+  var readFileSync = opts.readFileSync || fs.readFileSync;
+
+  var extensions = opts.extensions || ['.js'];
+  var y = opts.basedir || path.dirname(caller());
+
+  opts.paths = opts.paths || [];
+
+  if (/^(?:\.\.?(?:\/|$)|\/|([A-Za-z]:)?[\\\/])/.test(x)) {
+    var res = path.resolve(y, x);
+    if (x === '..') res += '/';
+    var m = loadAsFileSync(res) || loadAsDirectorySync(res);
+    if (m) return m;
+  } else {
+    var n = loadNodeModulesSync(x, y);
+    if (n) return n;
+  }
+
+  if (core[x]) return x;
+
+  var err = new Error("Cannot find module '" + x + "' from '" + y + "'");
+  err.code = 'MODULE_NOT_FOUND';
+  throw err;
+
+  function loadAsFileSync(x) {
+    if (isFile(x)) {
+      return x;
+    }
+
+    for (var i = 0; i < extensions.length; i++) {
+      var file = x + extensions[i];
+      if (isFile(file)) {
+        return file;
+      }
+    }
+  }
+
+  function loadAsDirectorySync(x) {
+    var pkgfile = path.join(x, '/package.json');
+    if (isFile(pkgfile)) {
+      var body = readFileSync(pkgfile, 'utf8');
+      try {
+        var pkg = JSON.parse(body);
+        if (opts.packageFilter) {
+          pkg = opts.packageFilter(pkg, x);
+        }
+
+        if (pkg.main) {
+          var m = loadAsFileSync(path.resolve(x, pkg.main));
+          if (m) return m;
+          var n = loadAsDirectorySync(path.resolve(x, pkg.main));
+          if (n) return n;
+        }
+      } catch (e) {}
+    }
+
+    return loadAsFileSync(path.join(x, '/index'));
+  }
+
+  function loadNodeModulesSync(x, start) {
+    var dirs = nodeModulesPaths(start, opts);
+    for (var i = 0; i < dirs.length; i++) {
+      var dir = dirs[i];
+      var m = loadAsFileSync(path.join(dir, '/', x));
+      if (m) return m;
+      var n = loadAsDirectorySync(path.join(dir, '/', x));
+      if (n) return n;
+    }
+  }
+};
+

From f8e02f3d425727a0451b0b6344d5545a07f3029a Mon Sep 17 00:00:00 2001
From: Tony Valderrama <tony.valderrama@outlook.com>
Date: Mon, 21 Aug 2017 11:37:36 -0700
Subject: [PATCH 02/20] Strip out extraneous core and caller dependencies.

---
 packages/jest-resolve/src/default_resolver.js | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/packages/jest-resolve/src/default_resolver.js b/packages/jest-resolve/src/default_resolver.js
index 338e87f86a72..542d1f74bd8e 100644
--- a/packages/jest-resolve/src/default_resolver.js
+++ b/packages/jest-resolve/src/default_resolver.js
@@ -38,10 +38,8 @@ module.exports = defaultResolver;
  * resolve logic, taken directly from resolve.sync
  */
 
-var core = require('./core');
 var fs = require('fs');
 var path = require('path');
-var caller = require('./caller.js');
 var nodeModulesPaths = require('./node-modules-paths.js');
 
 function resolveSync(x, options) {
@@ -58,7 +56,7 @@ function resolveSync(x, options) {
   var readFileSync = opts.readFileSync || fs.readFileSync;
 
   var extensions = opts.extensions || ['.js'];
-  var y = opts.basedir || path.dirname(caller());
+  var y = opts.basedir;
 
   opts.paths = opts.paths || [];
 
@@ -72,8 +70,6 @@ function resolveSync(x, options) {
     if (n) return n;
   }
 
-  if (core[x]) return x;
-
   var err = new Error("Cannot find module '" + x + "' from '" + y + "'");
   err.code = 'MODULE_NOT_FOUND';
   throw err;

From a80d26782a93e2b62add4e9e3d949eb73342fe0a Mon Sep 17 00:00:00 2001
From: Tony Valderrama <tony.valderrama@outlook.com>
Date: Mon, 21 Aug 2017 11:40:46 -0700
Subject: [PATCH 03/20] Pull node-modules-path into codebase as well.
 (incomplete)

---
 packages/jest-resolve/src/default_resolver.js | 39 ++++++++++++++++++-
 1 file changed, 38 insertions(+), 1 deletion(-)

diff --git a/packages/jest-resolve/src/default_resolver.js b/packages/jest-resolve/src/default_resolver.js
index 542d1f74bd8e..304bf83f2eac 100644
--- a/packages/jest-resolve/src/default_resolver.js
+++ b/packages/jest-resolve/src/default_resolver.js
@@ -40,7 +40,6 @@ module.exports = defaultResolver;
 
 var fs = require('fs');
 var path = require('path');
-var nodeModulesPaths = require('./node-modules-paths.js');
 
 function resolveSync(x, options) {
   var opts = options || {};
@@ -121,3 +120,41 @@ function resolveSync(x, options) {
   }
 };
 
+/**
+ * node-modules-path, taken directly from resolve.sync
+ */
+
+var parse = path.parse || require('path-parse');
+
+function nodeModulesPaths(start, opts) {
+  var modules = opts && opts.moduleDirectory
+    ? [].concat(opts.moduleDirectory)
+    : ['node_modules']
+  ;
+
+  // ensure that `start` is an absolute path at this point,
+  // resolving against the process' current working directory
+  start = path.resolve(start);
+
+  var prefix = '/';
+  if (/^([A-Za-z]:)/.test(start)) {
+    prefix = '';
+  } else if (/^\\\\/.test(start)) {
+    prefix = '\\\\';
+  }
+
+  var paths = [start];
+  var parsed = parse(start);
+  while (parsed.dir !== paths[paths.length - 1]) {
+    paths.push(parsed.dir);
+    parsed = parse(parsed.dir);
+  }
+
+  var dirs = paths.reduce(function (dirs, aPath) {
+    return dirs.concat(modules.map(function (moduleDir) {
+      return path.join(prefix, aPath, moduleDir);
+    }));
+  }, []);
+
+  return opts && opts.paths ? dirs.concat(opts.paths) : dirs;
+};

From a4f2641a554499229746046268870eeaed168707 Mon Sep 17 00:00:00 2001
From: Tony Valderrama <tony.valderrama@outlook.com>
Date: Mon, 21 Aug 2017 11:42:23 -0700
Subject: [PATCH 04/20] Remove dependency on path-parse. Assume existence of
 path.parse (added in v0.11.15).

---
 packages/jest-resolve/src/default_resolver.js | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/packages/jest-resolve/src/default_resolver.js b/packages/jest-resolve/src/default_resolver.js
index 304bf83f2eac..b470b0bd07cc 100644
--- a/packages/jest-resolve/src/default_resolver.js
+++ b/packages/jest-resolve/src/default_resolver.js
@@ -124,8 +124,6 @@ function resolveSync(x, options) {
  * node-modules-path, taken directly from resolve.sync
  */
 
-var parse = path.parse || require('path-parse');
-
 function nodeModulesPaths(start, opts) {
   var modules = opts && opts.moduleDirectory
     ? [].concat(opts.moduleDirectory)
@@ -144,10 +142,10 @@ function nodeModulesPaths(start, opts) {
   }
 
   var paths = [start];
-  var parsed = parse(start);
+  var parsed = path.parse(start);
   while (parsed.dir !== paths[paths.length - 1]) {
     paths.push(parsed.dir);
-    parsed = parse(parsed.dir);
+    parsed = path.parse(parsed.dir);
   }
 
   var dirs = paths.reduce(function (dirs, aPath) {

From b0dd6954bfe976118f309c0fa833ea5148b07678 Mon Sep 17 00:00:00 2001
From: Tony Valderrama <tony.valderrama@outlook.com>
Date: Mon, 21 Aug 2017 11:56:15 -0700
Subject: [PATCH 05/20] Use internal resolve within default_resolver.

---
 packages/jest-resolve/src/default_resolver.js | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/packages/jest-resolve/src/default_resolver.js b/packages/jest-resolve/src/default_resolver.js
index b470b0bd07cc..fb9ff10f0ee8 100644
--- a/packages/jest-resolve/src/default_resolver.js
+++ b/packages/jest-resolve/src/default_resolver.js
@@ -10,7 +10,6 @@
 
 import type {Path} from 'types/Config';
 
-import resolve from 'resolve';
 import browserResolve from 'browser-resolve';
 
 type ResolverOptions = {|
@@ -22,9 +21,9 @@ type ResolverOptions = {|
 |};
 
 function defaultResolver(path: Path, options: ResolverOptions) {
-  const resv = options.browser ? browserResolve : resolve;
+  const resolve = options.browser ? browserResolve.sync : resolveSync;
 
-  return resv.sync(path, {
+  return resolve(path, {
     basedir: options.basedir,
     extensions: options.extensions,
     moduleDirectory: options.moduleDirectory,

From 559315258bd1e0f3e833131d701aa831a7bf64c7 Mon Sep 17 00:00:00 2001
From: Tony Valderrama <tony.valderrama@outlook.com>
Date: Mon, 21 Aug 2017 12:07:41 -0700
Subject: [PATCH 06/20] Adhere to linter constraints.

---
 packages/jest-resolve/src/default_resolver.js | 92 ++++++++++---------
 1 file changed, 48 insertions(+), 44 deletions(-)

diff --git a/packages/jest-resolve/src/default_resolver.js b/packages/jest-resolve/src/default_resolver.js
index fb9ff10f0ee8..209652d442c2 100644
--- a/packages/jest-resolve/src/default_resolver.js
+++ b/packages/jest-resolve/src/default_resolver.js
@@ -37,38 +37,40 @@ module.exports = defaultResolver;
  * resolve logic, taken directly from resolve.sync
  */
 
-var fs = require('fs');
-var path = require('path');
+const fs = require('fs');
+const path = require('path');
 
 function resolveSync(x, options) {
-  var opts = options || {};
-  var isFile = opts.isFile || function (file) {
-    try {
-      var stat = fs.statSync(file);
-    } catch (e) {
-      if (e && e.code === 'ENOENT') return false;
-      throw e;
-    }
-    return stat.isFile() || stat.isFIFO();
-  };
-  var readFileSync = opts.readFileSync || fs.readFileSync;
+  const opts = options || {};
+  const isFile =
+    opts.isFile ||
+    function(file) {
+      try {
+        const stat = fs.statSync(file);
+        return stat.isFile() || stat.isFIFO();
+      } catch (e) {
+        if (e && e.code === 'ENOENT') return false;
+        throw e;
+      }
+    };
+  const readFileSync = opts.readFileSync || fs.readFileSync;
 
-  var extensions = opts.extensions || ['.js'];
-  var y = opts.basedir;
+  const extensions = opts.extensions || ['.js'];
+  const y = opts.basedir;
 
   opts.paths = opts.paths || [];
 
   if (/^(?:\.\.?(?:\/|$)|\/|([A-Za-z]:)?[\\\/])/.test(x)) {
-    var res = path.resolve(y, x);
+    let res = path.resolve(y, x);
     if (x === '..') res += '/';
-    var m = loadAsFileSync(res) || loadAsDirectorySync(res);
+    const m = loadAsFileSync(res) || loadAsDirectorySync(res);
     if (m) return m;
   } else {
-    var n = loadNodeModulesSync(x, y);
+    const n = loadNodeModulesSync(x, y);
     if (n) return n;
   }
 
-  var err = new Error("Cannot find module '" + x + "' from '" + y + "'");
+  const err = new Error("Cannot find module '" + x + "' from '" + y + "'");
   err.code = 'MODULE_NOT_FOUND';
   throw err;
 
@@ -77,8 +79,8 @@ function resolveSync(x, options) {
       return x;
     }
 
-    for (var i = 0; i < extensions.length; i++) {
-      var file = x + extensions[i];
+    for (let i = 0; i < extensions.length; i++) {
+      const file = x + extensions[i];
       if (isFile(file)) {
         return file;
       }
@@ -86,19 +88,19 @@ function resolveSync(x, options) {
   }
 
   function loadAsDirectorySync(x) {
-    var pkgfile = path.join(x, '/package.json');
+    const pkgfile = path.join(x, '/package.json');
     if (isFile(pkgfile)) {
-      var body = readFileSync(pkgfile, 'utf8');
+      const body = readFileSync(pkgfile, 'utf8');
       try {
-        var pkg = JSON.parse(body);
+        let pkg = JSON.parse(body);
         if (opts.packageFilter) {
           pkg = opts.packageFilter(pkg, x);
         }
 
         if (pkg.main) {
-          var m = loadAsFileSync(path.resolve(x, pkg.main));
+          const m = loadAsFileSync(path.resolve(x, pkg.main));
           if (m) return m;
-          var n = loadAsDirectorySync(path.resolve(x, pkg.main));
+          const n = loadAsDirectorySync(path.resolve(x, pkg.main));
           if (n) return n;
         }
       } catch (e) {}
@@ -108,50 +110,52 @@ function resolveSync(x, options) {
   }
 
   function loadNodeModulesSync(x, start) {
-    var dirs = nodeModulesPaths(start, opts);
-    for (var i = 0; i < dirs.length; i++) {
-      var dir = dirs[i];
-      var m = loadAsFileSync(path.join(dir, '/', x));
+    const dirs = nodeModulesPaths(start, opts);
+    for (let i = 0; i < dirs.length; i++) {
+      const dir = dirs[i];
+      const m = loadAsFileSync(path.join(dir, '/', x));
       if (m) return m;
-      var n = loadAsDirectorySync(path.join(dir, '/', x));
+      const n = loadAsDirectorySync(path.join(dir, '/', x));
       if (n) return n;
     }
   }
-};
+}
 
 /**
  * node-modules-path, taken directly from resolve.sync
  */
 
 function nodeModulesPaths(start, opts) {
-  var modules = opts && opts.moduleDirectory
-    ? [].concat(opts.moduleDirectory)
-    : ['node_modules']
-  ;
+  const modules =
+    opts && opts.moduleDirectory
+      ? [].concat(opts.moduleDirectory)
+      : ['node_modules'];
 
   // ensure that `start` is an absolute path at this point,
   // resolving against the process' current working directory
   start = path.resolve(start);
 
-  var prefix = '/';
+  let prefix = '/';
   if (/^([A-Za-z]:)/.test(start)) {
     prefix = '';
   } else if (/^\\\\/.test(start)) {
     prefix = '\\\\';
   }
 
-  var paths = [start];
-  var parsed = path.parse(start);
+  const paths = [start];
+  let parsed = path.parse(start);
   while (parsed.dir !== paths[paths.length - 1]) {
     paths.push(parsed.dir);
     parsed = path.parse(parsed.dir);
   }
 
-  var dirs = paths.reduce(function (dirs, aPath) {
-    return dirs.concat(modules.map(function (moduleDir) {
-      return path.join(prefix, aPath, moduleDir);
-    }));
+  const dirs = paths.reduce((dirs, aPath) => {
+    return dirs.concat(
+      modules.map(moduleDir => {
+        return path.join(prefix, aPath, moduleDir);
+      }),
+    );
   }, []);
 
   return opts && opts.paths ? dirs.concat(opts.paths) : dirs;
-};
+}

From 08bc70dcca288f089cb651a70cc50ec20d76ff3c Mon Sep 17 00:00:00 2001
From: Tony Valderrama <tony.valderrama@outlook.com>
Date: Mon, 21 Aug 2017 12:09:07 -0700
Subject: [PATCH 07/20] Extend basic error type with code property.

---
 packages/jest-resolve/src/default_resolver.js | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/packages/jest-resolve/src/default_resolver.js b/packages/jest-resolve/src/default_resolver.js
index 209652d442c2..048354191e5d 100644
--- a/packages/jest-resolve/src/default_resolver.js
+++ b/packages/jest-resolve/src/default_resolver.js
@@ -37,6 +37,8 @@ module.exports = defaultResolver;
  * resolve logic, taken directly from resolve.sync
  */
 
+type ErrorWithCode = Error & {code?: string};
+
 const fs = require('fs');
 const path = require('path');
 
@@ -70,7 +72,9 @@ function resolveSync(x, options) {
     if (n) return n;
   }
 
-  const err = new Error("Cannot find module '" + x + "' from '" + y + "'");
+  const err: ErrorWithCode = new Error(
+    "Cannot find module '" + x + "' from '" + y + "'",
+  );
   err.code = 'MODULE_NOT_FOUND';
   throw err;
 

From 942ddc7b8536dda75a589d110cc9e17a4e43902c Mon Sep 17 00:00:00 2001
From: Tony Valderrama <tony.valderrama@outlook.com>
Date: Mon, 21 Aug 2017 12:31:49 -0700
Subject: [PATCH 08/20] Fix typing and remove extraneous options.

---
 packages/jest-resolve/src/default_resolver.js | 66 +++++++++----------
 1 file changed, 30 insertions(+), 36 deletions(-)

diff --git a/packages/jest-resolve/src/default_resolver.js b/packages/jest-resolve/src/default_resolver.js
index 048354191e5d..dbf6e4e5ae83 100644
--- a/packages/jest-resolve/src/default_resolver.js
+++ b/packages/jest-resolve/src/default_resolver.js
@@ -20,7 +20,7 @@ type ResolverOptions = {|
   paths?: ?Array<Path>,
 |};
 
-function defaultResolver(path: Path, options: ResolverOptions) {
+function defaultResolver(path: Path, options: ResolverOptions): Path {
   const resolve = options.browser ? browserResolve.sync : resolveSync;
 
   return resolve(path, {
@@ -42,25 +42,22 @@ type ErrorWithCode = Error & {code?: string};
 const fs = require('fs');
 const path = require('path');
 
-function resolveSync(x, options) {
-  const opts = options || {};
-  const isFile =
-    opts.isFile ||
-    function(file) {
-      try {
-        const stat = fs.statSync(file);
-        return stat.isFile() || stat.isFIFO();
-      } catch (e) {
-        if (e && e.code === 'ENOENT') return false;
-        throw e;
-      }
-    };
-  const readFileSync = opts.readFileSync || fs.readFileSync;
+function resolveSync(x: Path, options: ResolverOptions): Path {
+  function isFile(file: Path): boolean {
+    try {
+      const stat = fs.statSync(file);
+      return stat.isFile() || stat.isFIFO();
+    } catch (e) {
+      if (e && e.code === 'ENOENT') return false;
+      throw e;
+    }
+  }
+  const readFileSync = fs.readFileSync;
 
-  const extensions = opts.extensions || ['.js'];
-  const y = opts.basedir;
+  const extensions = options.extensions || ['.js'];
+  const y = options.basedir;
 
-  opts.paths = opts.paths || [];
+  options.paths = options.paths || [];
 
   if (/^(?:\.\.?(?:\/|$)|\/|([A-Za-z]:)?[\\\/])/.test(x)) {
     let res = path.resolve(y, x);
@@ -78,7 +75,7 @@ function resolveSync(x, options) {
   err.code = 'MODULE_NOT_FOUND';
   throw err;
 
-  function loadAsFileSync(x) {
+  function loadAsFileSync(x: Path): ?Path {
     if (isFile(x)) {
       return x;
     }
@@ -89,22 +86,20 @@ function resolveSync(x, options) {
         return file;
       }
     }
+
+    return undefined;
   }
 
-  function loadAsDirectorySync(x) {
+  function loadAsDirectorySync(x: Path): ?Path {
     const pkgfile = path.join(x, '/package.json');
     if (isFile(pkgfile)) {
       const body = readFileSync(pkgfile, 'utf8');
       try {
-        let pkg = JSON.parse(body);
-        if (opts.packageFilter) {
-          pkg = opts.packageFilter(pkg, x);
-        }
-
-        if (pkg.main) {
-          const m = loadAsFileSync(path.resolve(x, pkg.main));
+        const pkgmain = JSON.parse(body).main;
+        if (pkgmain) {
+          const m = loadAsFileSync(path.resolve(x, pkgmain));
           if (m) return m;
-          const n = loadAsDirectorySync(path.resolve(x, pkg.main));
+          const n = loadAsDirectorySync(path.resolve(x, pkgmain));
           if (n) return n;
         }
       } catch (e) {}
@@ -113,8 +108,8 @@ function resolveSync(x, options) {
     return loadAsFileSync(path.join(x, '/index'));
   }
 
-  function loadNodeModulesSync(x, start) {
-    const dirs = nodeModulesPaths(start, opts);
+  function loadNodeModulesSync(x: Path, start: Path): ?Path {
+    const dirs = nodeModulesPaths(start, options);
     for (let i = 0; i < dirs.length; i++) {
       const dir = dirs[i];
       const m = loadAsFileSync(path.join(dir, '/', x));
@@ -122,6 +117,8 @@ function resolveSync(x, options) {
       const n = loadAsDirectorySync(path.join(dir, '/', x));
       if (n) return n;
     }
+
+    return undefined;
   }
 }
 
@@ -129,11 +126,8 @@ function resolveSync(x, options) {
  * node-modules-path, taken directly from resolve.sync
  */
 
-function nodeModulesPaths(start, opts) {
-  const modules =
-    opts && opts.moduleDirectory
-      ? [].concat(opts.moduleDirectory)
-      : ['node_modules'];
+function nodeModulesPaths(start: Path, options: ResolverOptions): Path[] {
+  const modules = ['node_modules'];
 
   // ensure that `start` is an absolute path at this point,
   // resolving against the process' current working directory
@@ -161,5 +155,5 @@ function nodeModulesPaths(start, opts) {
     );
   }, []);
 
-  return opts && opts.paths ? dirs.concat(opts.paths) : dirs;
+  return options.paths ? dirs.concat(options.paths) : dirs;
 }

From d10676ab91221da82107da85e3b38da609c87031 Mon Sep 17 00:00:00 2001
From: Tony Valderrama <tony.valderrama@outlook.com>
Date: Mon, 21 Aug 2017 12:37:30 -0700
Subject: [PATCH 09/20] Gather helper methods at end of resolveSync().

---
 packages/jest-resolve/src/default_resolver.js | 85 +++++++++----------
 1 file changed, 42 insertions(+), 43 deletions(-)

diff --git a/packages/jest-resolve/src/default_resolver.js b/packages/jest-resolve/src/default_resolver.js
index dbf6e4e5ae83..3e780331c67a 100644
--- a/packages/jest-resolve/src/default_resolver.js
+++ b/packages/jest-resolve/src/default_resolver.js
@@ -33,25 +33,15 @@ function defaultResolver(path: Path, options: ResolverOptions): Path {
 
 module.exports = defaultResolver;
 
-/**
- * resolve logic, taken directly from resolve.sync
+/*
+ * resolve logic, adapted from resolve.sync
  */
-
 type ErrorWithCode = Error & {code?: string};
 
 const fs = require('fs');
 const path = require('path');
 
 function resolveSync(x: Path, options: ResolverOptions): Path {
-  function isFile(file: Path): boolean {
-    try {
-      const stat = fs.statSync(file);
-      return stat.isFile() || stat.isFIFO();
-    } catch (e) {
-      if (e && e.code === 'ENOENT') return false;
-      throw e;
-    }
-  }
   const readFileSync = fs.readFileSync;
 
   const extensions = options.extensions || ['.js'];
@@ -75,6 +65,19 @@ function resolveSync(x: Path, options: ResolverOptions): Path {
   err.code = 'MODULE_NOT_FOUND';
   throw err;
 
+  /*
+   * helper functions
+   */
+  function isFile(file: Path): boolean {
+    try {
+      const stat = fs.statSync(file);
+      return stat.isFile() || stat.isFIFO();
+    } catch (e) {
+      if (e && e.code === 'ENOENT') return false;
+      throw e;
+    }
+  }
+
   function loadAsFileSync(x: Path): ?Path {
     if (isFile(x)) {
       return x;
@@ -109,7 +112,7 @@ function resolveSync(x: Path, options: ResolverOptions): Path {
   }
 
   function loadNodeModulesSync(x: Path, start: Path): ?Path {
-    const dirs = nodeModulesPaths(start, options);
+    const dirs = nodeModulesPaths(start);
     for (let i = 0; i < dirs.length; i++) {
       const dir = dirs[i];
       const m = loadAsFileSync(path.join(dir, '/', x));
@@ -120,40 +123,36 @@ function resolveSync(x: Path, options: ResolverOptions): Path {
 
     return undefined;
   }
-}
 
-/**
- * node-modules-path, taken directly from resolve.sync
- */
-
-function nodeModulesPaths(start: Path, options: ResolverOptions): Path[] {
-  const modules = ['node_modules'];
+  function nodeModulesPaths(start: Path): Path[] {
+    const modules = ['node_modules'];
 
-  // ensure that `start` is an absolute path at this point,
-  // resolving against the process' current working directory
-  start = path.resolve(start);
+    // ensure that `start` is an absolute path at this point,
+    // resolving against the process' current working directory
+    start = path.resolve(start);
 
-  let prefix = '/';
-  if (/^([A-Za-z]:)/.test(start)) {
-    prefix = '';
-  } else if (/^\\\\/.test(start)) {
-    prefix = '\\\\';
-  }
+    let prefix = '/';
+    if (/^([A-Za-z]:)/.test(start)) {
+      prefix = '';
+    } else if (/^\\\\/.test(start)) {
+      prefix = '\\\\';
+    }
 
-  const paths = [start];
-  let parsed = path.parse(start);
-  while (parsed.dir !== paths[paths.length - 1]) {
-    paths.push(parsed.dir);
-    parsed = path.parse(parsed.dir);
-  }
+    const paths = [start];
+    let parsed = path.parse(start);
+    while (parsed.dir !== paths[paths.length - 1]) {
+      paths.push(parsed.dir);
+      parsed = path.parse(parsed.dir);
+    }
 
-  const dirs = paths.reduce((dirs, aPath) => {
-    return dirs.concat(
-      modules.map(moduleDir => {
-        return path.join(prefix, aPath, moduleDir);
-      }),
-    );
-  }, []);
+    const dirs = paths.reduce((dirs, aPath) => {
+      return dirs.concat(
+        modules.map(moduleDir => {
+          return path.join(prefix, aPath, moduleDir);
+        }),
+      );
+    }, []);
 
-  return options.paths ? dirs.concat(options.paths) : dirs;
+    return options.paths ? dirs.concat(options.paths) : dirs;
+  }
 }

From d15ec91ace2270b2800335349baf2bac8f559699 Mon Sep 17 00:00:00 2001
From: Tony Valderrama <tony.valderrama@outlook.com>
Date: Mon, 21 Aug 2017 12:41:33 -0700
Subject: [PATCH 10/20] Rename "start" parameter to more obvious "basedir".

---
 packages/jest-resolve/src/default_resolver.js | 26 +++++++++----------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/packages/jest-resolve/src/default_resolver.js b/packages/jest-resolve/src/default_resolver.js
index 3e780331c67a..ac0ee0f23157 100644
--- a/packages/jest-resolve/src/default_resolver.js
+++ b/packages/jest-resolve/src/default_resolver.js
@@ -45,22 +45,22 @@ function resolveSync(x: Path, options: ResolverOptions): Path {
   const readFileSync = fs.readFileSync;
 
   const extensions = options.extensions || ['.js'];
-  const y = options.basedir;
+  const basedir = options.basedir;
 
   options.paths = options.paths || [];
 
   if (/^(?:\.\.?(?:\/|$)|\/|([A-Za-z]:)?[\\\/])/.test(x)) {
-    let res = path.resolve(y, x);
+    let res = path.resolve(basedir, x);
     if (x === '..') res += '/';
     const m = loadAsFileSync(res) || loadAsDirectorySync(res);
     if (m) return m;
   } else {
-    const n = loadNodeModulesSync(x, y);
+    const n = loadNodeModulesSync(x, basedir);
     if (n) return n;
   }
 
   const err: ErrorWithCode = new Error(
-    "Cannot find module '" + x + "' from '" + y + "'",
+    "Cannot find module '" + x + "' from '" + basedir + "'",
   );
   err.code = 'MODULE_NOT_FOUND';
   throw err;
@@ -111,8 +111,8 @@ function resolveSync(x: Path, options: ResolverOptions): Path {
     return loadAsFileSync(path.join(x, '/index'));
   }
 
-  function loadNodeModulesSync(x: Path, start: Path): ?Path {
-    const dirs = nodeModulesPaths(start);
+  function loadNodeModulesSync(x: Path, basedir: Path): ?Path {
+    const dirs = nodeModulesPaths(basedir);
     for (let i = 0; i < dirs.length; i++) {
       const dir = dirs[i];
       const m = loadAsFileSync(path.join(dir, '/', x));
@@ -124,22 +124,22 @@ function resolveSync(x: Path, options: ResolverOptions): Path {
     return undefined;
   }
 
-  function nodeModulesPaths(start: Path): Path[] {
+  function nodeModulesPaths(basedir: Path): Path[] {
     const modules = ['node_modules'];
 
-    // ensure that `start` is an absolute path at this point,
+    // ensure that `basedir` is an absolute path at this point,
     // resolving against the process' current working directory
-    start = path.resolve(start);
+    basedir = path.resolve(basedir);
 
     let prefix = '/';
-    if (/^([A-Za-z]:)/.test(start)) {
+    if (/^([A-Za-z]:)/.test(basedir)) {
       prefix = '';
-    } else if (/^\\\\/.test(start)) {
+    } else if (/^\\\\/.test(basedir)) {
       prefix = '\\\\';
     }
 
-    const paths = [start];
-    let parsed = path.parse(start);
+    const paths = [basedir];
+    let parsed = path.parse(basedir);
     while (parsed.dir !== paths[paths.length - 1]) {
       paths.push(parsed.dir);
       parsed = path.parse(parsed.dir);

From 24e9b18f058e5e107da051b4e0affb63585bbfa7 Mon Sep 17 00:00:00 2001
From: Tony Valderrama <tony.valderrama@outlook.com>
Date: Mon, 21 Aug 2017 12:49:47 -0700
Subject: [PATCH 11/20] Avoid shadowing basedir variable.

---
 packages/jest-resolve/src/default_resolver.js | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/packages/jest-resolve/src/default_resolver.js b/packages/jest-resolve/src/default_resolver.js
index ac0ee0f23157..85f9cd993fa3 100644
--- a/packages/jest-resolve/src/default_resolver.js
+++ b/packages/jest-resolve/src/default_resolver.js
@@ -111,8 +111,8 @@ function resolveSync(x: Path, options: ResolverOptions): Path {
     return loadAsFileSync(path.join(x, '/index'));
   }
 
-  function loadNodeModulesSync(x: Path, basedir: Path): ?Path {
-    const dirs = nodeModulesPaths(basedir);
+  function loadNodeModulesSync(x: Path): ?Path {
+    const dirs = nodeModulesPaths();
     for (let i = 0; i < dirs.length; i++) {
       const dir = dirs[i];
       const m = loadAsFileSync(path.join(dir, '/', x));
@@ -124,22 +124,22 @@ function resolveSync(x: Path, options: ResolverOptions): Path {
     return undefined;
   }
 
-  function nodeModulesPaths(basedir: Path): Path[] {
+  function nodeModulesPaths(): Path[] {
     const modules = ['node_modules'];
 
     // ensure that `basedir` is an absolute path at this point,
     // resolving against the process' current working directory
-    basedir = path.resolve(basedir);
+    const basedirAbs = path.resolve(basedir);
 
     let prefix = '/';
-    if (/^([A-Za-z]:)/.test(basedir)) {
+    if (/^([A-Za-z]:)/.test(basedirAbs)) {
       prefix = '';
-    } else if (/^\\\\/.test(basedir)) {
+    } else if (/^\\\\/.test(basedirAbs)) {
       prefix = '\\\\';
     }
 
-    const paths = [basedir];
-    let parsed = path.parse(basedir);
+    const paths = [basedirAbs];
+    let parsed = path.parse(basedirAbs);
     while (parsed.dir !== paths[paths.length - 1]) {
       paths.push(parsed.dir);
       parsed = path.parse(parsed.dir);

From 7e46c07a9a9d6aa824385b09e3c3ca6b908c2af1 Mon Sep 17 00:00:00 2001
From: Tony Valderrama <tony.valderrama@outlook.com>
Date: Mon, 21 Aug 2017 12:50:53 -0700
Subject: [PATCH 12/20] Inline loadNodeModulesSync() method.

---
 packages/jest-resolve/src/default_resolver.js | 23 +++++++------------
 1 file changed, 8 insertions(+), 15 deletions(-)

diff --git a/packages/jest-resolve/src/default_resolver.js b/packages/jest-resolve/src/default_resolver.js
index 85f9cd993fa3..97baf8968038 100644
--- a/packages/jest-resolve/src/default_resolver.js
+++ b/packages/jest-resolve/src/default_resolver.js
@@ -55,8 +55,14 @@ function resolveSync(x: Path, options: ResolverOptions): Path {
     const m = loadAsFileSync(res) || loadAsDirectorySync(res);
     if (m) return m;
   } else {
-    const n = loadNodeModulesSync(x, basedir);
-    if (n) return n;
+    const dirs = nodeModulesPaths();
+    for (let i = 0; i < dirs.length; i++) {
+      const dir = dirs[i];
+      const m = loadAsFileSync(path.join(dir, '/', x));
+      if (m) return m;
+      const n = loadAsDirectorySync(path.join(dir, '/', x));
+      if (n) return n;
+    }
   }
 
   const err: ErrorWithCode = new Error(
@@ -111,19 +117,6 @@ function resolveSync(x: Path, options: ResolverOptions): Path {
     return loadAsFileSync(path.join(x, '/index'));
   }
 
-  function loadNodeModulesSync(x: Path): ?Path {
-    const dirs = nodeModulesPaths();
-    for (let i = 0; i < dirs.length; i++) {
-      const dir = dirs[i];
-      const m = loadAsFileSync(path.join(dir, '/', x));
-      if (m) return m;
-      const n = loadAsDirectorySync(path.join(dir, '/', x));
-      if (n) return n;
-    }
-
-    return undefined;
-  }
-
   function nodeModulesPaths(): Path[] {
     const modules = ['node_modules'];
 

From 73ccd44c3c53cb9411845bbb28626499c2c15a6b Mon Sep 17 00:00:00 2001
From: Tony Valderrama <tony.valderrama@outlook.com>
Date: Mon, 21 Aug 2017 12:53:43 -0700
Subject: [PATCH 13/20] Clarify relative import vs node_modules.

---
 packages/jest-resolve/src/default_resolver.js | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/packages/jest-resolve/src/default_resolver.js b/packages/jest-resolve/src/default_resolver.js
index 97baf8968038..35a76bb8a0be 100644
--- a/packages/jest-resolve/src/default_resolver.js
+++ b/packages/jest-resolve/src/default_resolver.js
@@ -40,6 +40,7 @@ type ErrorWithCode = Error & {code?: string};
 
 const fs = require('fs');
 const path = require('path');
+const REGEX_RELATIVE_IMPORT = /^(?:\.\.?(?:\/|$)|\/|([A-Za-z]:)?[\\\/])/;
 
 function resolveSync(x: Path, options: ResolverOptions): Path {
   const readFileSync = fs.readFileSync;
@@ -49,12 +50,14 @@ function resolveSync(x: Path, options: ResolverOptions): Path {
 
   options.paths = options.paths || [];
 
-  if (/^(?:\.\.?(?:\/|$)|\/|([A-Za-z]:)?[\\\/])/.test(x)) {
+  if (REGEX_RELATIVE_IMPORT.test(x)) {
+    // resolve relative import
     let res = path.resolve(basedir, x);
     if (x === '..') res += '/';
     const m = loadAsFileSync(res) || loadAsDirectorySync(res);
     if (m) return m;
   } else {
+    // otherwise search for node_modules
     const dirs = nodeModulesPaths();
     for (let i = 0; i < dirs.length; i++) {
       const dir = dirs[i];

From 513f1d2f21fedeb49e9d278a5261d24b4a83accb Mon Sep 17 00:00:00 2001
From: Tony Valderrama <tony.valderrama@outlook.com>
Date: Mon, 21 Aug 2017 12:54:44 -0700
Subject: [PATCH 14/20] Use import instead of require.

---
 packages/jest-resolve/src/default_resolver.js | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/packages/jest-resolve/src/default_resolver.js b/packages/jest-resolve/src/default_resolver.js
index 35a76bb8a0be..fd3c94f83c9c 100644
--- a/packages/jest-resolve/src/default_resolver.js
+++ b/packages/jest-resolve/src/default_resolver.js
@@ -38,8 +38,9 @@ module.exports = defaultResolver;
  */
 type ErrorWithCode = Error & {code?: string};
 
-const fs = require('fs');
-const path = require('path');
+import fs from 'fs';
+import path from 'path';
+
 const REGEX_RELATIVE_IMPORT = /^(?:\.\.?(?:\/|$)|\/|([A-Za-z]:)?[\\\/])/;
 
 function resolveSync(x: Path, options: ResolverOptions): Path {

From e625b8a9f33be9b9451df174dcc41d55fd4588ed Mon Sep 17 00:00:00 2001
From: Tony Valderrama <tony.valderrama@outlook.com>
Date: Mon, 21 Aug 2017 13:00:34 -0700
Subject: [PATCH 15/20] Small logic and formatting simplifications.

---
 packages/jest-resolve/src/default_resolver.js | 24 +++++++------------
 1 file changed, 9 insertions(+), 15 deletions(-)

diff --git a/packages/jest-resolve/src/default_resolver.js b/packages/jest-resolve/src/default_resolver.js
index fd3c94f83c9c..aad859d42c00 100644
--- a/packages/jest-resolve/src/default_resolver.js
+++ b/packages/jest-resolve/src/default_resolver.js
@@ -53,19 +53,18 @@ function resolveSync(x: Path, options: ResolverOptions): Path {
 
   if (REGEX_RELATIVE_IMPORT.test(x)) {
     // resolve relative import
-    let res = path.resolve(basedir, x);
-    if (x === '..') res += '/';
-    const m = loadAsFileSync(res) || loadAsDirectorySync(res);
+    let target = path.resolve(basedir, x);
+    if (x === '..') target += '/';
+    const m = loadAsFileSync(target) || loadAsDirectorySync(target);
     if (m) return m;
   } else {
     // otherwise search for node_modules
     const dirs = nodeModulesPaths();
     for (let i = 0; i < dirs.length; i++) {
       const dir = dirs[i];
-      const m = loadAsFileSync(path.join(dir, '/', x));
+      const target = path.join(dir, '/', x);
+      const m = loadAsFileSync(target) || loadAsDirectorySync(target);
       if (m) return m;
-      const n = loadAsDirectorySync(path.join(dir, '/', x));
-      if (n) return n;
     }
   }
 
@@ -89,15 +88,11 @@ function resolveSync(x: Path, options: ResolverOptions): Path {
   }
 
   function loadAsFileSync(x: Path): ?Path {
-    if (isFile(x)) {
-      return x;
-    }
+    if (isFile(x)) return x;
 
     for (let i = 0; i < extensions.length; i++) {
       const file = x + extensions[i];
-      if (isFile(file)) {
-        return file;
-      }
+      if (isFile(file)) return file;
     }
 
     return undefined;
@@ -110,10 +105,9 @@ function resolveSync(x: Path, options: ResolverOptions): Path {
       try {
         const pkgmain = JSON.parse(body).main;
         if (pkgmain) {
-          const m = loadAsFileSync(path.resolve(x, pkgmain));
+          const target = path.resolve(x, pkgmain);
+          const m = loadAsFileSync(target) || loadAsDirectorySync(target);
           if (m) return m;
-          const n = loadAsDirectorySync(path.resolve(x, pkgmain));
-          if (n) return n;
         }
       } catch (e) {}
     }

From eb980f38358470c1cba8e4c264baf82f25e98e14 Mon Sep 17 00:00:00 2001
From: Tony Valderrama <tony.valderrama@outlook.com>
Date: Mon, 21 Aug 2017 13:20:49 -0700
Subject: [PATCH 16/20] Use isBuiltinModule() to detect core modules. Restore
 use of moduleDirectory option.

---
 packages/jest-resolve/src/default_resolver.js | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/packages/jest-resolve/src/default_resolver.js b/packages/jest-resolve/src/default_resolver.js
index aad859d42c00..9d8ddb8f4949 100644
--- a/packages/jest-resolve/src/default_resolver.js
+++ b/packages/jest-resolve/src/default_resolver.js
@@ -40,6 +40,7 @@ type ErrorWithCode = Error & {code?: string};
 
 import fs from 'fs';
 import path from 'path';
+import isBuiltinModule from 'is-builtin-module';
 
 const REGEX_RELATIVE_IMPORT = /^(?:\.\.?(?:\/|$)|\/|([A-Za-z]:)?[\\\/])/;
 
@@ -68,6 +69,8 @@ function resolveSync(x: Path, options: ResolverOptions): Path {
     }
   }
 
+  if (isBuiltinModule(x)) return x;
+
   const err: ErrorWithCode = new Error(
     "Cannot find module '" + x + "' from '" + basedir + "'",
   );
@@ -116,7 +119,10 @@ function resolveSync(x: Path, options: ResolverOptions): Path {
   }
 
   function nodeModulesPaths(): Path[] {
-    const modules = ['node_modules'];
+    const modules =
+      options && options.moduleDirectory
+        ? [].concat(options.moduleDirectory)
+        : ['node_modules'];
 
     // ensure that `basedir` is an absolute path at this point,
     // resolving against the process' current working directory

From b04689981f310973c7adc12d70b4841dd6f23c96 Mon Sep 17 00:00:00 2001
From: Tony Valderrama <tony.valderrama@outlook.com>
Date: Mon, 21 Aug 2017 13:25:37 -0700
Subject: [PATCH 17/20] Remove package dependency on resolve.

---
 packages/jest-resolve/package.json | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/packages/jest-resolve/package.json b/packages/jest-resolve/package.json
index 637fcc8447d3..6bd44f3e3da7 100644
--- a/packages/jest-resolve/package.json
+++ b/packages/jest-resolve/package.json
@@ -10,8 +10,7 @@
   "dependencies": {
     "browser-resolve": "^1.11.2",
     "chalk": "^2.0.1",
-    "is-builtin-module": "^1.0.0",
-    "resolve": "^1.3.2"
+    "is-builtin-module": "^1.0.0"
   },
   "devDependencies": {
     "jest-haste-map": "^20.0.4"

From 580f0c8c86924b2a197d14158fc0c35990682959 Mon Sep 17 00:00:00 2001
From: Tony Valderrama <tony.valderrama@outlook.com>
Date: Mon, 21 Aug 2017 13:57:45 -0700
Subject: [PATCH 18/20] Make node_modules_paths available to resolver core
 logic, rather than just default_resolver.

---
 packages/jest-resolve/src/default_resolver.js | 39 ++-------------
 packages/jest-resolve/src/index.js            |  2 +-
 .../jest-resolve/src/node_modules_paths.js    | 47 +++++++++++++++++++
 3 files changed, 51 insertions(+), 37 deletions(-)
 create mode 100644 packages/jest-resolve/src/node_modules_paths.js

diff --git a/packages/jest-resolve/src/default_resolver.js b/packages/jest-resolve/src/default_resolver.js
index 9d8ddb8f4949..af561fbfbc36 100644
--- a/packages/jest-resolve/src/default_resolver.js
+++ b/packages/jest-resolve/src/default_resolver.js
@@ -42,6 +42,8 @@ import fs from 'fs';
 import path from 'path';
 import isBuiltinModule from 'is-builtin-module';
 
+import nodeModulesPaths from './node_modules_paths';
+
 const REGEX_RELATIVE_IMPORT = /^(?:\.\.?(?:\/|$)|\/|([A-Za-z]:)?[\\\/])/;
 
 function resolveSync(x: Path, options: ResolverOptions): Path {
@@ -60,7 +62,7 @@ function resolveSync(x: Path, options: ResolverOptions): Path {
     if (m) return m;
   } else {
     // otherwise search for node_modules
-    const dirs = nodeModulesPaths();
+    const dirs = nodeModulesPaths(basedir, options);
     for (let i = 0; i < dirs.length; i++) {
       const dir = dirs[i];
       const target = path.join(dir, '/', x);
@@ -117,39 +119,4 @@ function resolveSync(x: Path, options: ResolverOptions): Path {
 
     return loadAsFileSync(path.join(x, '/index'));
   }
-
-  function nodeModulesPaths(): Path[] {
-    const modules =
-      options && options.moduleDirectory
-        ? [].concat(options.moduleDirectory)
-        : ['node_modules'];
-
-    // ensure that `basedir` is an absolute path at this point,
-    // resolving against the process' current working directory
-    const basedirAbs = path.resolve(basedir);
-
-    let prefix = '/';
-    if (/^([A-Za-z]:)/.test(basedirAbs)) {
-      prefix = '';
-    } else if (/^\\\\/.test(basedirAbs)) {
-      prefix = '\\\\';
-    }
-
-    const paths = [basedirAbs];
-    let parsed = path.parse(basedirAbs);
-    while (parsed.dir !== paths[paths.length - 1]) {
-      paths.push(parsed.dir);
-      parsed = path.parse(parsed.dir);
-    }
-
-    const dirs = paths.reduce((dirs, aPath) => {
-      return dirs.concat(
-        modules.map(moduleDir => {
-          return path.join(prefix, aPath, moduleDir);
-        }),
-      );
-    }, []);
-
-    return options.paths ? dirs.concat(options.paths) : dirs;
-  }
 }
diff --git a/packages/jest-resolve/src/index.js b/packages/jest-resolve/src/index.js
index b96b80a1bdfc..90565d999210 100644
--- a/packages/jest-resolve/src/index.js
+++ b/packages/jest-resolve/src/index.js
@@ -14,7 +14,7 @@ import type {ResolveModuleConfig} from 'types/Resolve';
 
 import fs from 'fs';
 import path from 'path';
-import nodeModulesPaths from 'resolve/lib/node-modules-paths';
+import nodeModulesPaths from './node_modules_paths';
 import isBuiltinModule from 'is-builtin-module';
 import defaultResolver from './default_resolver.js';
 import chalk from 'chalk';
diff --git a/packages/jest-resolve/src/node_modules_paths.js b/packages/jest-resolve/src/node_modules_paths.js
new file mode 100644
index 000000000000..84c183d4db5e
--- /dev/null
+++ b/packages/jest-resolve/src/node_modules_paths.js
@@ -0,0 +1,47 @@
+import type {Path} from 'types/Config';
+import path from 'path';
+
+type NodeModulesPathsOptions = {|
+  moduleDirectory?: Array<string>,
+  paths?: ?Array<Path>,
+|};
+
+function nodeModulesPaths(
+  basedir: Path,
+  options: NodeModulesPathsOptions,
+): Path[] {
+  const modules =
+    options && options.moduleDirectory
+      ? [].concat(options.moduleDirectory)
+      : ['node_modules'];
+
+  // ensure that `basedir` is an absolute path at this point,
+  // resolving against the process' current working directory
+  const basedirAbs = path.resolve(basedir);
+
+  let prefix = '/';
+  if (/^([A-Za-z]:)/.test(basedirAbs)) {
+    prefix = '';
+  } else if (/^\\\\/.test(basedirAbs)) {
+    prefix = '\\\\';
+  }
+
+  const paths = [basedirAbs];
+  let parsed = path.parse(basedirAbs);
+  while (parsed.dir !== paths[paths.length - 1]) {
+    paths.push(parsed.dir);
+    parsed = path.parse(parsed.dir);
+  }
+
+  const dirs = paths.reduce((dirs, aPath) => {
+    return dirs.concat(
+      modules.map(moduleDir => {
+        return path.join(prefix, aPath, moduleDir);
+      }),
+    );
+  }, []);
+
+  return options.paths ? dirs.concat(options.paths) : dirs;
+}
+
+module.exports = nodeModulesPaths;

From 33133808fc289da15460235c4a772afaed5d20bf Mon Sep 17 00:00:00 2001
From: Tony Valderrama <tony.valderrama@outlook.com>
Date: Mon, 21 Aug 2017 14:31:51 -0700
Subject: [PATCH 19/20] Add standard header to node_modules_paths.js. Add
 adaptation note to default_resolver.js.

---
 packages/jest-resolve/src/default_resolver.js   |  2 +-
 packages/jest-resolve/src/node_modules_paths.js | 12 ++++++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/packages/jest-resolve/src/default_resolver.js b/packages/jest-resolve/src/default_resolver.js
index af561fbfbc36..51e2c2acfb81 100644
--- a/packages/jest-resolve/src/default_resolver.js
+++ b/packages/jest-resolve/src/default_resolver.js
@@ -34,7 +34,7 @@ function defaultResolver(path: Path, options: ResolverOptions): Path {
 module.exports = defaultResolver;
 
 /*
- * resolve logic, adapted from resolve.sync
+ * Adapted from: https://github.com/substack/node-resolve
  */
 type ErrorWithCode = Error & {code?: string};
 
diff --git a/packages/jest-resolve/src/node_modules_paths.js b/packages/jest-resolve/src/node_modules_paths.js
index 84c183d4db5e..d5aacc9c871e 100644
--- a/packages/jest-resolve/src/node_modules_paths.js
+++ b/packages/jest-resolve/src/node_modules_paths.js
@@ -1,3 +1,15 @@
+/**
+ * Copyright (c) 2014, Facebook, Inc. All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * Adapted from: https://github.com/substack/node-resolve
+ *
+ * @flow
+ */
+
 import type {Path} from 'types/Config';
 import path from 'path';
 

From de104b06480e767253645a3b53d7361d52490e2f Mon Sep 17 00:00:00 2001
From: Tony Valderrama <tony.valderrama@outlook.com>
Date: Mon, 21 Aug 2017 18:25:31 -0700
Subject: [PATCH 20/20] Trim out unused options when calling
 nodeModulesPaths().

---
 packages/jest-resolve/src/default_resolver.js | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/packages/jest-resolve/src/default_resolver.js b/packages/jest-resolve/src/default_resolver.js
index 51e2c2acfb81..2ed74a9823b3 100644
--- a/packages/jest-resolve/src/default_resolver.js
+++ b/packages/jest-resolve/src/default_resolver.js
@@ -62,7 +62,10 @@ function resolveSync(x: Path, options: ResolverOptions): Path {
     if (m) return m;
   } else {
     // otherwise search for node_modules
-    const dirs = nodeModulesPaths(basedir, options);
+    const dirs = nodeModulesPaths(basedir, {
+      moduleDirectory: options.moduleDirectory,
+      paths: options.paths,
+    });
     for (let i = 0; i < dirs.length; i++) {
       const dir = dirs[i];
       const target = path.join(dir, '/', x);