maxDepth for unflatten

index.js

@@ -54,9 +54,14 @@ function flatten (target, opts) {
 function unflatten (target, opts) {
   opts = opts || {}
 
+  if (opts.maxDepth === 0) {
+    return target
+  }
+
   const delimiter = opts.delimiter || '.'
   const overwrite = opts.overwrite || false
   const transformKey = opts.transformKey || keyIdentity
+  const maxDepth = opts.maxDepth || Infinity
   const result = {}
 
   const isbuffer = isBuffer(target)
@@ -80,7 +85,6 @@ function unflatten (target, opts) {
   function addKeys (keyPrefix, recipient, target) {
     return Object.keys(target).reduce(function (result, key) {
       result[keyPrefix + delimiter + key] = target[key]
-
       return result
     }, recipient)
   }
@@ -119,6 +123,7 @@ function unflatten (target, opts) {
     let key1 = getkey(split.shift())
     let key2 = getkey(split[0])
     let recipient = result
+    let depth = 1
 
     while (key2 !== undefined) {
       if (key1 === '__proto__') {
@@ -144,13 +149,18 @@ function unflatten (target, opts) {
       }
 
       recipient = recipient[key1]
-      if (split.length > 0) {
+      if (split.length > 0 && depth < maxDepth) {
         key1 = getkey(split.shift())
         key2 = getkey(split[0])
+      } else {
+        key1 = getkey(split.join(delimiter))
+        key2 = undefined
       }
+      depth += 1
     }
 
     // unflatten again for 'messy objects'
+    opts.maxDepth -= depth
     recipient[key1] = unflatten(target[key], opts)
   })
 

test/test.js

@@ -231,6 +231,51 @@ suite('Unflatten', function () {
     }))
   })
 
+  test('Custom Depth', function () {
+    assert.deepEqual(unflatten({
+      'hello.brave': {
+        'new.world.again': 'good morning'
+      },
+      'all.you.need.is.love': 'love is all you need'
+    },
+    {
+      maxDepth: 3
+    }), {
+      hello: {
+        brave: {
+          'new': {
+            'world.again': 'good morning'
+          }
+        }
+      },
+      all: {
+        you: {
+          need: {
+            'is.love': 'love is all you need'
+          }
+        }
+      }
+    })
+  })
+
+  test('Zero Depth', function () {
+    assert.deepEqual({
+      hello: {
+        world: {
+          again: 'good morning'
+        }
+      }
+    }, unflatten({
+      hello: {
+        world: {
+          again: 'good morning'
+        }
+      }
+    }, {
+      maxDepth: 0
+    }))
+  })
+
   test('Multiple Keys', function () {
     assert.deepStrictEqual({
       hello: {