fix: avoid overwriting the default values of options with undefined (#…

…1018)

* fix(conventional-changelog-core): avoid overwriting the default values of options with undefined

* test(conventional-changelog-core): add tests for merge-config

* refactor(conventional-changelog-core): optimize omitUndefinedValueProps to one loop

packages/conventional-changelog-core/lib/merge-config.js

@@ -53,10 +53,27 @@ function guessNextTag (previousTag, version) {
   return version
 }
 
+function omitUndefinedValueProps (obj) {
+  if (!obj) {
+    return {}
+  }
+
+  const omittedObj = {}
+
+  for (const key in obj) {
+    if (obj[key] !== undefined) {
+      omittedObj[key] = obj[key]
+    }
+  }
+
+  return omittedObj
+}
+
 async function mergeConfig (options, context, gitRawCommitsOpts, parserOpts, writerOpts, gitRawExecOpts) {
   let configPromise
   let pkgPromise
 
+  options = omitUndefinedValueProps(options)
   context = context || {}
   gitRawCommitsOpts = gitRawCommitsOpts || {}
   gitRawExecOpts = gitRawExecOpts || {}

packages/conventional-changelog-core/test/merge-config.spec.js

@@ -0,0 +1,61 @@
+'use strict'
+const mergeConfig = require('../lib/merge-config')
+const expect = require('chai').expect
+const describe = require('mocha').describe
+
+const defaultOptions = {
+  append: false,
+  releaseCount: 1,
+  skipUnstable: false,
+  lernaPackage: null,
+  outputUnreleased: true
+}
+
+describe('merge-config', function () {
+  it('should return passed options', async function () {
+    const options = {
+      append: true,
+      releaseCount: 0,
+      skipUnstable: true,
+      debug: function () {},
+      warn: function () {},
+      transform: function () {},
+      lernaPackage: 'foo',
+      tagPrefix: 'bar',
+      outputUnreleased: true,
+      pkg: {
+        path: 'baz',
+        transform: function () {}
+      }
+    }
+    const config = await mergeConfig(options)
+    expect(config.options).to.deep.include(options)
+  })
+
+  it('should return default options if empty options is passed', async function () {
+    const { options } = await mergeConfig({})
+    expect(options).to.include(defaultOptions)
+  })
+
+  it('should return default options when no options is passed', async function () {
+    const { options } = await mergeConfig()
+    expect(options).to.include(defaultOptions)
+  })
+
+  it('should return default options when null is passed', async function () {
+    const { options } = await mergeConfig(null)
+    expect(options).to.include(defaultOptions)
+  })
+
+  it('should return default options when undefined value is passed', async function () {
+    const options = {
+      append: undefined,
+      releaseCount: undefined,
+      skipUnstable: undefined,
+      lernaPackage: undefined,
+      outputUnreleased: undefined
+    }
+    const config = await mergeConfig(options)
+    expect(config.options).to.include(defaultOptions)
+  })
+})