Add original field to remove operation

diff.ts

@@ -25,7 +25,7 @@ differentiates between.
 */
 
 export interface AddOperation     { op: 'add',     path: string, value: any                  }
-export interface RemoveOperation  { op: 'remove',  path: string                              }
+export interface RemoveOperation  { op: 'remove',  path: string, original?: any              }
 export interface ReplaceOperation { op: 'replace', path: string, value: any, original?: any  }
 export interface MoveOperation    { op: 'move',    from: string, path: string                }
 export interface CopyOperation    { op: 'copy',    from: string, path: string                }
@@ -113,7 +113,7 @@ export function intersection(objects: ArrayLike<{[index: string]: any}>): string
 }
 
 interface ArrayAdd     { op: 'add',     index: number, value: any }
-interface ArrayRemove  { op: 'remove',  index: number }
+interface ArrayRemove  { op: 'remove',  index: number, original?: any }
 interface ArrayReplace { op: 'replace', index: number, original: any, value: any }
 /** These are not proper Operation objects, but will be converted into
 Operation objects eventually. {index} indicates the actual target position,
@@ -203,6 +203,7 @@ export function diffArrays<T>(input: T[], output: T[], ptr: Pointer, diff: Diff
           const remove_operation: ArrayRemove = {
             op: 'remove',
             index: i - 1,
+            original: input[i - 1],
           }
           alternatives.push(appendArrayOperation(remove_base, remove_operation))
         }
@@ -264,6 +265,7 @@ export function diffArrays<T>(input: T[], output: T[], ptr: Pointer, diff: Diff
       const operation = {
         op: array_operation.op,
         path: ptr.add(String(array_operation.index + padding)).toString(),
+        original: array_operation.original
       }
       // padding--
       return [operations.concat(operation), padding - 1]
@@ -281,7 +283,7 @@ export function diffObjects(input: any, output: any, ptr: Pointer, diff: Diff =
   // if a key is in input but not output -> remove it
   const operations: Operation[] = []
   subtract(input, output).forEach(key => {
-    operations.push({op: 'remove', path: ptr.add(key).toString()})
+    operations.push({op: 'remove', path: ptr.add(key).toString(), original: input[key]})
   })
   // if a key is in output but not input -> add it
   subtract(output, input).forEach(key => {

dist/rfc6902.js

@@ -299,6 +299,7 @@
                       const remove_operation = {
                           op: 'remove',
                           index: i - 1,
+                          original: input[i - 1],
                       };
                       alternatives.push(appendArrayOperation(remove_base, remove_operation));
                   }
@@ -359,6 +360,7 @@
               const operation = {
                   op: array_operation.op,
                   path: ptr.add(String(array_operation.index + padding)).toString(),
+                  original: array_operation.original
               };
               // padding--
               return [operations.concat(operation), padding - 1];
@@ -375,7 +377,7 @@
       // if a key is in input but not output -> remove it
       const operations = [];
       subtract(input, output).forEach(key => {
-          operations.push({ op: 'remove', path: ptr.add(key).toString() });
+          operations.push({ op: 'remove', path: ptr.add(key).toString(), original: input[key] });
       });
       // if a key is in output but not input -> add it
       subtract(output, input).forEach(key => {

test/issues.ts

@@ -25,8 +25,8 @@ test('issues/3', t => {
   const input = {arr: ['1', '2', '2']}
   const output = {arr: ['1']}
   const expected_patch: Operation[] = [
-    {op: 'remove', path: '/arr/1'},
-    {op: 'remove', path: '/arr/1'},
+    {op: 'remove', path: '/arr/1', original: '2'},
+    {op: 'remove', path: '/arr/1', original: '2'},
   ]
   checkRoundtrip(t, input, output, expected_patch)
 })
@@ -36,7 +36,7 @@ test('issues/4', t => {
   const output = ['B', 'A']
   const expected_patch: Operation[] = [
     {op: 'add', path: '/0', value: 'B'},
-    {op: 'remove', path: '/2'},
+    {op: 'remove', path: '/2', original: 'B'},
   ]
   checkRoundtrip(t, input, output, expected_patch)
 })
@@ -121,7 +121,7 @@ test('issues/29', t => {
     stop_recursing: ['a'],
   }
   const expected_patch: Operation[] = [
-    {op: 'remove', path: '/normal/1'},
+    {op: 'remove', path: '/normal/1', original: 'b'},
     {op: 'replace', path: '/stop_recursing', value: ['a']},
   ]
   const actual_patch = createPatch(input, output, customDiff)
@@ -130,7 +130,7 @@ test('issues/29', t => {
   const nested_input = {root: input}
   const nested_output = {root: output}
   const nested_expected_patch: Operation[] = [
-    {op: 'remove', path: '/root/normal/1'},
+    {op: 'remove', path: '/root/normal/1', 'original': 'b'},
     {op: 'replace', path: '/root/stop_recursing', value: ['a']},
   ]
   const nested_actual_patch = createPatch(nested_input, nested_output, customDiff)

test/spec.yaml

@@ -23,7 +23,7 @@
   input:
     {"baz": "qux", "foo": "bar"}
   patch:
-    - {op: "remove", path: "/baz"}
+    - {op: "remove", path: "/baz", original: "qux"}
   output:
     {"foo": "bar"}
   results: [null]
@@ -33,7 +33,7 @@
   input:
     {"foo": [ "bar", "qux", "baz" ]}
   patch:
-    - {op: "remove", path: "/foo/1"}
+    - {op: "remove", path: "/foo/1", original: "qux"}
   output:
     {"foo": [ "bar", "baz" ]}
   results: [null]