don't re-require babel plugins every time buildOptions is called.

Author: jamestalmage

lib/test-transformer.js

@@ -9,19 +9,23 @@ function factory(cacheDir) {
 	var createEspowerPlugin = require('babel-plugin-espower/create');
 	var babel = require('babel-core');
 	var enhanceAssert = require('./enhance-assert');
+
 	var convertSourceMap = require('convert-source-map');
+	var presetStage2 = require('babel-preset-stage-2');
+	var presetES2015 = require('babel-preset-es2015');
+	var transformRuntime = require('babel-plugin-transform-runtime');
 
-	function buildOptions(filename, code) {
-		// initialize power-assert
-		var powerAssert = createEspowerPlugin(babel, {
-			patterns: enhanceAssert.PATTERNS
-		});
+	// initialize power-assert
+	var powerAssert = createEspowerPlugin(babel, {
+		patterns: enhanceAssert.PATTERNS
+	});
 
+	function buildOptions(filename, code) {
 		var sourceMap = convertSourceMap.fromSource(code) || convertSourceMap.fromMapFileSource(code, path.dirname(filename));
 
 		return {
-			presets: [require('babel-preset-stage-2'), require('babel-preset-es2015')],
-			plugins: [powerAssert, require('babel-plugin-transform-runtime')],
+			presets: [presetStage2, presetES2015],
+			plugins: [powerAssert, transformRuntime],
 			filename: filename,
 			sourceMaps: true,
 			ast: false,