Add renamePath

API.md

@@ -27,6 +27,7 @@
 | [`reject`](#reject) | `a -> Promise Error` |
 | [`rename`](#rename) | `String -> String -> { k: v } -> { k: v }` |
 | [`renameAll`](#renameall) | `{ k: v } -> { k: v } -> { k: v }` |
+| [`renamePath`](#renamepath) | `[String] -> String -> { k: v } -> { k: v }` |
 | [`resolve`](#resolve) | `a -> Promise a` |
 | [`tapP`](#tapp) | `(a -> Promise b) -> a -> Promise a` |
 | [`useWithP`](#usewithp) | `(a -> b -> Promise c) -> [(d -> Promise a), (e -> Promise b)] -> (d -> e -> Promise c)` |
@@ -440,9 +441,25 @@ renameAll :: { k: v } -> { k: v } -> { k: v }
 Rename multiple properties on an object to have different keys.
 
 ```js
-const orig = { first_name: 'Miles', last_name: 'Callisto' }
-renameAll({ first_name: 'firstName', last_name: 'lastName' }, orig)
-//=> { firstName: 'Miles', lastName: 'Callisto' }
+const orig = { user: { first_name: 'Miles', last_name: 'Callisto' } }
+renameAll({ user: { first_name: 'firstName' } }, orig)
+//=> { user: { firstName: 'Miles', last_name: 'Callisto' } }
+```
+
+### renamePath
+
+`@articulate/funky/lib/renamePath`
+
+```haskell
+renamePath :: [String] -> String -> { k: v } -> { k: v }
+```
+
+Rename a deeply nested path on an object to have a different key.
+
+```js
+const orig = { user: { first_name: 'Miles', last_name: 'Callisto' } }
+renamePath(['user', 'first_name'], 'firstName', orig)
+//=> { user: { firstName: 'Miles', last_name: 'Callisto' } }
 ```
 
 ### resolve

index.js

@@ -23,6 +23,7 @@ exports.promisify    = require('./lib/promisify')
 exports.reject       = require('./lib/reject')
 exports.rename       = require('./lib/rename')
 exports.renameAll    = require('./lib/renameAll')
+exports.renamePath   = require('./lib/renamePath')
 exports.resolve      = require('./lib/resolve')
 exports.tapP         = require('./lib/tapP')
 exports.useWithP     = require('./lib/useWithP')

src/renamePath.js

@@ -0,0 +1,12 @@
+const assoc = require('ramda/src/assoc')
+const curry = require('ramda/src/curry')
+
+const rename = require('./rename')
+
+// renamePath :: [String] -> String -> { k: v } -> { k: v }
+const renamePath = ([ head, ...tail ], to, obj) =>
+  tail.length
+    ? assoc(head, renamePath(tail, to, obj[head]), obj)
+    : rename(head, to, obj)
+
+module.exports = curry(renamePath)

test/renamePath.js

@@ -0,0 +1,18 @@
+const { expect } = require('chai')
+
+const { renamePath } = require('..')
+
+describe('renamePath', () => {
+  const orig     = { a: { b: 'b' }, c: 'c' }
+  const expected = { a: { B: 'b' }, c: 'c' }
+
+  it('renames a deeply nested path on an object', () =>
+    expect(renamePath(['a', 'b'], 'B', orig)).to.eql(expected)
+  )
+
+  it('is curried', () => {
+    expect(renamePath(['a', 'b'])('B', orig)).to.eql(expected)
+    expect(renamePath(['a', 'b'], 'B')(orig)).to.eql(expected)
+    expect(renamePath(['a', 'b'])('B')(orig)).to.eql(expected)
+  })
+})