fixing renameAll to allow a from and a to to have the same name

src/renameAll.js

@@ -2,22 +2,33 @@ const curry = require('ramda/src/curry')
 
 // renameAll :: { k: v } -> { k: v } -> { k: v }
 const renameAll = (renames, obj) => {
-  obj = Object.assign({}, obj)
+  const newObj = {}
+  const tosMap = {}
+
+  for (let k in obj) {
+    newObj[k] = obj[k]
+  }
 
   for (let frum in renames) {
-    if (!(frum in obj)) continue
+    if (!(frum in obj)) {
+      continue
+    }
 
     const to = renames[frum]
 
     if (typeof to === 'object') {
-      obj[frum] = renameAll(to, obj[frum])
+      newObj[frum] = renameAll(to, obj[frum])
     } else {
-      obj[to] = obj[frum]
-      delete obj[frum]
+      tosMap[to] = true
+      newObj[to] = obj[frum]
+
+      if (!tosMap[frum]) {
+        delete newObj[frum]
+      }
     }
   }
 
-  return obj
+  return newObj
 }
 
 module.exports = curry(renameAll)

test/renameAll.js

@@ -8,23 +8,29 @@ describe('renameAll', () => {
     name: 'bird',
     sounds: {
       call: 'chirp'
-    }
+    },
+    title: 'My title',
+    latestTitle: 'haha (business)',
   }
 
   const renames = {
     color: 'appearance',
     count: 'number',
     sounds: {
       call: 'say'
-    }
+    },
+    latestTitle: 'title',
+    title: 'updatedTitle',
   }
 
   const expected = {
     appearance: 'red',
     name: 'bird',
     sounds: {
       say: 'chirp'
-    }
+    },
+    title: 'haha (business)',
+    updatedTitle: 'My title',
   }
 
   it('renames multiple nested properties on an object using a name-map', () =>