fix: tolerate null prototype for config objects with extends (#1376)

Fixes #1372
yargs · Jul 23, 2019 · 3d26d11 · 3d26d11
1 parent 015eeb9
commit 3d26d11
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Showing 2 changed files with 15 additions and 1 deletion.
diff --git a/lib/apply-extends.js b/lib/apply-extends.js
@@ -19,7 +19,7 @@ function getPathToDefaultConfig (cwd, pathToExtend) {
 function applyExtends (config, cwd) {
   let defaultConfig = {}
 
-  if (config.hasOwnProperty('extends')) {
+  if (Object.prototype.hasOwnProperty.call(config, 'extends')) {
     if (typeof config.extends !== 'string') return defaultConfig
     const isPath = /\.json|\..*rc$/.test(config.extends)
     let pathToDefault = null

diff --git a/test/yargs.js b/test/yargs.js
@@ -1292,6 +1292,20 @@ describe('yargs dsl tests', () => {
         argv.z.should.equal(15)
       })
 
+      it('tolerates null prototype config objects', () => {
+        const argv = yargs
+          .config({
+            __proto__: null,
+            a: 2,
+            extends: './test/fixtures/extends/config_1.json'
+          })
+          .parse()
+
+        argv.a.should.equal(2)
+        argv.b.should.equal(22)
+        argv.z.should.equal(15)
+      })
+
       // see: https://www.npmjs.com/package/yargs-test-extends
       it('allows a module to be extended, rather than a JSON file', () => {
         const argv = yargs()