diff --git a/api.js b/api.js
index 058ab6523..92ccfcebd 100644
--- a/api.js
+++ b/api.js
@@ -127,7 +127,11 @@ Api.prototype._setupPrecompiler = function (files) {
 	this.options.cacheDir = cacheDir;
 
 	var isPowerAssertEnabled = this.options.powerAssert !== false;
-	this.precompiler = new CachingPrecompiler(cacheDir, this.options.babelConfig, isPowerAssertEnabled);
+	this.precompiler = new CachingPrecompiler({
+		path: cacheDir,
+		babel: this.options.babelConfig,
+		powerAssert: isPowerAssertEnabled
+	});
 };
 
 Api.prototype._run = function (files, options) {
diff --git a/lib/caching-precompiler.js b/lib/caching-precompiler.js
index f543f5dfa..d355372e2 100644
--- a/lib/caching-precompiler.js
+++ b/lib/caching-precompiler.js
@@ -3,24 +3,26 @@ var path = require('path');
 var fs = require('fs');
 var convertSourceMap = require('convert-source-map');
 var cachingTransform = require('caching-transform');
-var stripBom = require('strip-bom');
-var md5Hex = require('md5-hex');
 var packageHash = require('package-hash');
+var stripBom = require('strip-bom');
 var autoBind = require('auto-bind');
+var md5Hex = require('md5-hex');
 var babelConfigHelper = require('./babel-config');
 
-function CachingPrecompiler(cacheDirPath, babelConfig, powerAssert) {
+function CachingPrecompiler(options) {
 	if (!(this instanceof CachingPrecompiler)) {
 		throw new TypeError('Class constructor CachingPrecompiler cannot be invoked without \'new\'');
 	}
 
-	this.babelConfig = babelConfigHelper.validate(babelConfig);
-	this.powerAssert = powerAssert;
-	this.cacheDirPath = cacheDirPath;
-	this.fileHashes = {};
-
 	autoBind(this);
 
+	options = options || {};
+
+	this.babelConfig = babelConfigHelper.validate(options.babel);
+	this.cacheDirPath = options.path;
+	this.powerAssert = Boolean(options.powerAssert);
+	this.fileHashes = {};
+
 	this.transform = this._createTransform();
 }
 
@@ -37,14 +39,10 @@ CachingPrecompiler.prototype.precompileFile = function (filePath) {
 };
 
 // conditionally called by caching-transform when precompiling is required
-CachingPrecompiler.prototype._factory = function () {
-	this._init();
-
-	return this._transform;
-};
-
 CachingPrecompiler.prototype._init = function () {
 	this.babel = require('babel-core');
+
+	return this._transform;
 };
 
 CachingPrecompiler.prototype._transform = function (code, filePath, hash) {
@@ -57,15 +55,8 @@ CachingPrecompiler.prototype._transform = function (code, filePath, hash) {
 	var mapPath = path.join(this.cacheDirPath, hash + '.js.map');
 	fs.writeFileSync(mapPath, JSON.stringify(result.map));
 
-	// When loading the test file, test workers intercept the require call and
-	// load the cached code instead. Libraries like nyc may also be intercepting
-	// require calls, however they won't know that different code was loaded.
-	// They may then attempt to resolve a source map from the original file
-	// location.
-	//
-	// Add a source map file comment to the cached code. The file path is
-	// relative from the directory of the original file to where the source map
-	// is cached. This will allow the source map to be resolved.
+	// append source map comment to transformed code
+	// so that other libraries (like nyc) can find the source map
 	var dirPath = path.dirname(filePath);
 	var relativeMapPath = path.relative(dirPath, mapPath);
 	var comment = convertSourceMap.generateMapFileComment(relativeMapPath);
@@ -74,14 +65,18 @@ CachingPrecompiler.prototype._transform = function (code, filePath, hash) {
 };
 
 CachingPrecompiler.prototype._createTransform = function () {
-	var salt = packageHash.sync(
-		[require.resolve('../package.json')].concat(babelConfigHelper.pluginPackages),
-		JSON.stringify(this.babelConfig),
-		process.version.split('.')[0]
-	);
+	var pluginPackages = babelConfigHelper.pluginPackages;
+	var avaPackage = require.resolve('../package.json');
+	var packages = [avaPackage].concat(pluginPackages);
+
+	var majorNodeVersion = process.version.split('.')[0];
+	var babelConfig = JSON.stringify(this.babelConfig);
+	var packageSalt = babelConfig + majorNodeVersion;
+
+	var salt = packageHash.sync(packages, packageSalt);
 
 	return cachingTransform({
-		factory: this._factory,
+		factory: this._init,
 		cacheDir: this.cacheDirPath,
 		hash: this._generateHash,
 		salt: salt,
diff --git a/profile.js b/profile.js
index 3cda7afef..786f19226 100644
--- a/profile.js
+++ b/profile.js
@@ -60,8 +60,14 @@ var cacheDir = findCacheDir({
 	name: 'ava',
 	files: [file]
 }) || uniqueTempDir();
+
+var precompiler = new CachingPrecompiler({
+	path: cacheDir,
+	babel: conf.babel
+});
+
 var precompiled = {};
-precompiled[file] = new CachingPrecompiler(cacheDir, conf.babel).precompileFile(file);
+precompiled[file] = precompiler.precompileFile(file);
 
 var opts = {
 	file: file,
diff --git a/test/caching-precompiler.js b/test/caching-precompiler.js
index 502e3d320..0ab717c8f 100644
--- a/test/caching-precompiler.js
+++ b/test/caching-precompiler.js
@@ -25,7 +25,7 @@ sinon.spy(babel, 'transform');
 
 test('creation with new', function (t) {
 	var tempDir = uniqueTempDir();
-	var precompiler = new CachingPrecompiler(tempDir, null);
+	var precompiler = new CachingPrecompiler({path: tempDir});
 	t.is(precompiler.cacheDirPath, tempDir);
 	t.end();
 });
@@ -33,14 +33,14 @@ test('creation with new', function (t) {
 test('must be called with new', function (t) {
 	t.throws(function () {
 		var cachingPrecompiler = CachingPrecompiler;
-		cachingPrecompiler(uniqueTempDir(), null);
+		cachingPrecompiler({path: uniqueTempDir()});
 	}, {message: 'Class constructor CachingPrecompiler cannot be invoked without \'new\''});
 	t.end();
 });
 
 test('adds files and source maps to the cache directory as needed', function (t) {
 	var tempDir = uniqueTempDir();
-	var precompiler = new CachingPrecompiler(tempDir, null);
+	var precompiler = new CachingPrecompiler({path: tempDir});
 
 	t.false(fs.existsSync(tempDir), 'cache directory is not created before it is needed');
 
@@ -56,7 +56,7 @@ test('adds files and source maps to the cache directory as needed', function (t)
 
 test('adds a map file comment to the cached files', function (t) {
 	var tempDir = uniqueTempDir();
-	var precompiler = new CachingPrecompiler(tempDir, null);
+	var precompiler = new CachingPrecompiler({path: tempDir});
 
 	precompiler.precompileFile(fixture('es2015.js'));
 
@@ -84,7 +84,11 @@ test('adds a map file comment to the cached files', function (t) {
 
 test('uses default babel options when babelConfig === "default"', function (t) {
 	var tempDir = uniqueTempDir();
-	var precompiler = new CachingPrecompiler(tempDir, 'default');
+	var precompiler = new CachingPrecompiler({
+		path: tempDir,
+		babel: 'default'
+	});
+
 	babel.transform.reset();
 
 	precompiler.precompileFile(fixture('es2015.js'));
@@ -104,7 +108,11 @@ test('uses default babel options when babelConfig === "default"', function (t) {
 
 test('allows babel config from package.json/babel when babelConfig === "inherit"', function (t) {
 	var tempDir = uniqueTempDir();
-	var precompiler = new CachingPrecompiler(tempDir, 'inherit');
+	var precompiler = new CachingPrecompiler({
+		path: tempDir,
+		babel: 'inherit'
+	});
+
 	babel.transform.reset();
 
 	precompiler.precompileFile(fixture('es2015.js'));
@@ -122,7 +130,8 @@ test('allows babel config from package.json/babel when babelConfig === "inherit"
 
 test('does not modify plugins array in babelConfig', function (t) {
 	var plugins = [];
-	var precompiler = new CachingPrecompiler(uniqueTempDir(), {
+	var precompiler = new CachingPrecompiler({
+		path: uniqueTempDir(),
 		plugins: plugins
 	});
 
diff --git a/test/fork.js b/test/fork.js
index f21f71945..2314e6a80 100644
--- a/test/fork.js
+++ b/test/fork.js
@@ -5,7 +5,7 @@ var _fork = require('../lib/fork.js');
 var CachingPrecompiler = require('../lib/caching-precompiler');
 
 var cacheDir = path.join(__dirname, '../node_modules/.cache/ava');
-var precompiler = new CachingPrecompiler(cacheDir);
+var precompiler = new CachingPrecompiler({path: cacheDir});
 
 function fork(testPath) {
 	var hash = precompiler.precompileFile(testPath);
diff --git a/test/hooks.js b/test/hooks.js
index 82b612052..31aac8cca 100644
--- a/test/hooks.js
+++ b/test/hooks.js
@@ -6,7 +6,7 @@ var _fork = require('../lib/fork.js');
 var CachingPrecompiler = require('../lib/caching-precompiler');
 
 var cacheDir = path.join(__dirname, '../node_modules/.cache/ava');
-var precompiler = new CachingPrecompiler(cacheDir);
+var precompiler = new CachingPrecompiler({path: cacheDir});
 
 function fork(testPath) {
 	var hash = precompiler.precompileFile(testPath);