1 files changed, 19 insertions, 5 deletions
diff --git a/deps/npm/node_modules/yargs/lib/apply-extends.js b/deps/npm/node_modules/yargs/lib/apply-extends.js
index 530b022ac57..643c91335a0 100644
--- a/deps/npm/node_modules/yargs/lib/apply-extends.js
+++ b/deps/npm/node_modules/yargs/lib/apply-extends.js
@@ -16,12 +16,26 @@ function getPathToDefaultConfig (cwd, pathToExtend) {
   return path.resolve(cwd, pathToExtend)
 }
 
-function applyExtends (config, cwd) {
+function mergeDeep (config1, config2) {
+  const target = {}
+  const isObject = obj => obj && typeof obj === 'object' && !Array.isArray(obj)
+  Object.assign(target, config1)
+  for (let key of Object.keys(config2)) {
+    if (isObject(config2[key]) && isObject(target[key])) {
+      target[key] = mergeDeep(config1[key], config2[key])
+    } else {
+      target[key] = config2[key]
+    }
+  }
+  return target
+}
+
+function applyExtends (config, cwd, mergeExtends) {
   let defaultConfig = {}
 
-  if (config.hasOwnProperty('extends')) {
+  if (Object.prototype.hasOwnProperty.call(config, 'extends')) {
     if (typeof config.extends !== 'string') return defaultConfig
-    const isPath = /\.json$/.test(config.extends)
+    const isPath = /\.json|\..*rc$/.test(config.extends)
     let pathToDefault = null
     if (!isPath) {
       try {
@@ -42,12 +56,12 @@ function applyExtends (config, cwd) {
 
     defaultConfig = isPath ? JSON.parse(fs.readFileSync(pathToDefault, 'utf8')) : require(config.extends)
     delete config.extends
-    defaultConfig = applyExtends(defaultConfig, path.dirname(pathToDefault))
+    defaultConfig = applyExtends(defaultConfig, path.dirname(pathToDefault), mergeExtends)
   }
 
   previouslyVisitedConfigs = []
 
-  return Object.assign({}, defaultConfig, config)
+  return mergeExtends ? mergeDeep(defaultConfig, config) : Object.assign({}, defaultConfig, config)
 }
 
 module.exports = applyExtends