From a3936aa21e89b9a7e4f3bc05d3e56c1eff6a6a79 Mon Sep 17 00:00:00 2001
From: Corey Farrell <git@cfware.com>
Date: Sun, 5 May 2019 00:40:33 -0400
Subject: [PATCH] feat: add `strip-aliased` and `strip-dashed` configuration
 options. (#172)

---
 README.md            | 43 ++++++++++++++++++++++++++++
 index.js             | 21 +++++++++++++-
 test/yargs-parser.js | 67 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 130 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index e1f8abe1..94bbe46b 100644
--- a/README.md
+++ b/README.md
@@ -340,6 +340,49 @@ node example.js -a run b -x y
 { _: [ 'run', 'b', '-x', 'y' ], a: true }
 ```
 
+### strip aliased
+
+* default: `false`
+* key: `strip-aliased`
+
+Should aliases be removed before returning results?
+
+_If disabled:_
+
+```sh
+node example.js --test-field 1
+{ _: [], 'test-field': 1, testField: 1, 'test-alias': 1, testAlias: 1 }
+```
+
+_If enabled:_
+
+```sh
+node example.js --test-field 1
+{ _: [], 'test-field': 1, testField: 1 }
+```
+
+### strip dashed
+
+* default: `false`
+* key: `strip-dashed`
+
+Should dashed keys be removed before returning results?  This option has no effect if
+`camel-case-exansion` is disabled.
+
+_If disabled:_
+
+```sh
+node example.js --test-field 1
+{ _: [], 'test-field': 1, testField: 1 }
+```
+
+_If enabled:_
+
+```sh
+node example.js --test-field 1
+{ _: [], testField: 1 }
+```
+
 ## Special Thanks
 
 The yargs project evolves from optimist and minimist. It owes its
diff --git a/index.js b/index.js
index 546cae06..ed54b8d6 100644
--- a/index.js
+++ b/index.js
@@ -24,7 +24,9 @@ function parse (args, opts) {
     'populate--': false,
     'combine-arrays': false,
     'set-placeholder-key': false,
-    'halt-at-non-option': false
+    'halt-at-non-option': false,
+    'strip-aliased': false,
+    'strip-dashed': false
   }, opts.configuration)
   var defaults = opts.default || {}
   var configObjects = opts.configObjects || []
@@ -331,6 +333,23 @@ function parse (args, opts) {
     argv[notFlagsArgv].push(key)
   })
 
+  if (configuration['camel-case-expansion'] && configuration['strip-dashed']) {
+    Object.keys(argv).filter(key => key !== '--' && key.includes('-')).forEach(key => {
+      delete argv[key]
+    })
+  }
+
+  if (configuration['strip-aliased']) {
+    // XXX Switch to [].concat(...Object.values(aliases)) once node.js 6 is dropped
+    ;[].concat(...Object.keys(aliases).map(k => aliases[k])).forEach(alias => {
+      if (configuration['camel-case-expansion']) {
+        delete argv[alias.split('.').map(prop => camelCase(prop)).join('.')]
+      }
+
+      delete argv[alias]
+    })
+  }
+
   // how many arguments should we consume, based
   // on the nargs option?
   function eatNargs (i, key, args) {
diff --git a/test/yargs-parser.js b/test/yargs-parser.js
index c625ce97..fcff562a 100644
--- a/test/yargs-parser.js
+++ b/test/yargs-parser.js
@@ -2874,4 +2874,71 @@ describe('yargs-parser', function () {
     })
     argv.bar.should.equal('hello')
   })
+
+  describe('stripping', function () {
+    it('strip-dashed removes expected fields from argv', function () {
+      const argv = parser([ '--test-value', '1' ], {
+        number: ['test-value'],
+        alias: {
+          'test-value': ['alt-test']
+        },
+        configuration: {
+          'strip-dashed': true
+        }
+      })
+      argv.should.deep.equal({
+        _: [],
+        'testValue': 1,
+        'altTest': 1
+      })
+    })
+
+    it('strip-aliased removes expected fields from argv', function () {
+      const argv = parser([ '--test-value', '1' ], {
+        number: ['test-value'],
+        alias: {
+          'test-value': ['alt-test']
+        },
+        configuration: {
+          'strip-aliased': true
+        }
+      })
+      argv.should.deep.equal({
+        _: [],
+        'test-value': 1,
+        'testValue': 1
+      })
+    })
+
+    it('strip-aliased and strip-dashed combined removes expected fields from argv', function () {
+      const argv = parser([ '--test-value', '1' ], {
+        number: ['test-value'],
+        alias: {
+          'test-value': ['alt-test']
+        },
+        configuration: {
+          'strip-aliased': true,
+          'strip-dashed': true
+        }
+      })
+      argv.should.deep.equal({
+        _: [],
+        'testValue': 1
+      })
+    })
+
+    it('ignores strip-dashed if camel-case-expansion is disabled', function () {
+      const argv = parser([ '--test-value', '1' ], {
+        number: ['test-value'],
+        configuration: {
+          'camel-case-expansion': false,
+          'strip-dashed': true
+        }
+      })
+      argv.should.deep.equal({
+        _: [],
+        'test-value': 1
+      })
+    })
+  })
 })