make more readable for undefined -> null

Author: motdotla

lib/main.js

@@ -259,8 +259,12 @@ function _resolveHome (envPath) {
 }
 
 function _configOptions (options = {}) {
-  // explicit `undefined` must not mask DOTENV_* env settings
-  const defined = Object.fromEntries(Object.entries(options).filter(([, v]) => v !== undefined))
+  const defined = { ...options }
+
+  for (const key of Object.keys(defined)) {
+    if (defined[key] === undefined) delete defined[key]
+  }
+
   return { ...optionsFromEnv(), ...defined }
 }
 

tests/test-config.js

@@ -77,6 +77,20 @@ t.test('undefined options do not override DOTENV_CONFIG_* defaults', ct => {
   ct.end()
 })
 
+t.test('null options use environment defaults', ct => {
+  process.env.DOTENV_CONFIG_PATH = 'tests/.env.local'
+  process.env.DOTENV_CONFIG_QUIET = 'true'
+  errorStub = sinon.stub(console, 'error')
+
+  const result = dotenv.config(null)
+
+  ct.equal(result.error, undefined)
+  ct.equal(result.parsed.BASIC, 'local_basic')
+  ct.equal(process.env.BASIC, 'local_basic')
+  ct.ok(errorStub.notCalled)
+  ct.end()
+})
+
 t.test('takes string for path option', ct => {
   const testPath = 'tests/.env'
   const env = dotenv.config({ path: testPath })