diff --git a/src/bindings/em/patch.cc b/src/bindings/em/patch.cc
index 2f660615..b4e9ddbb 100644
--- a/src/bindings/em/patch.cc
+++ b/src/bindings/em/patch.cc
@@ -36,6 +36,21 @@ Patch * deserialize(std::vector<uint8_t> const & vec)
     return new Patch(vec);
 }
 
+Point get_old_extent(Patch::Hunk const & hunk)
+{
+    return hunk.old_end.traversal(hunk.old_start);
+}
+
+Point get_new_extent(Patch::Hunk const & hunk)
+{
+    return hunk.new_end.traversal(hunk.new_start);
+}
+
+template <typename T>
+void hunk_set_noop(Patch::Hunk & hunk, T const &)
+{
+}
+
 EMSCRIPTEN_BINDINGS(Patch) {
 
     emscripten::class_<Patch>("Patch")
@@ -81,6 +96,13 @@ EMSCRIPTEN_BINDINGS(Patch) {
         .field("oldText", WRAP_FIELD(Patch::Hunk, old_text))
         .field("newText", WRAP_FIELD(Patch::Hunk, new_text))
 
+        // The following fields are legacy only (most notably, TextBuffer doesn't work without them)
+
+        .field("start", WRAP_FIELD(Patch::Hunk, new_start))
+
+        .field("oldExtent", &get_old_extent, &hunk_set_noop<Point>)
+        .field("newExtent", &get_new_extent, &hunk_set_noop<Point>)
+
         ;
 
 }
diff --git a/test/js/patch.test.js b/test/js/patch.test.js
index d36ad078..c8c66867 100644
--- a/test/js/patch.test.js
+++ b/test/js/patch.test.js
@@ -34,6 +34,18 @@ describe('Patch', function () {
     patch.delete();
   })
 
+  it('expose legacy fields', function () {
+    const patch = new Patch({ mergeAdjacentHunks: false })
+
+    patch.splice({row: 0, column: 10}, {row: 0, column: 0}, {row: 1, column: 5})
+    patch.splice({row: 1, column: 5}, {row: 0, column: 2}, {row: 0, column: 8})
+
+    const hunk = patch.getHunks()[0];
+
+    assert.ok(hunk.oldExtent);
+    assert.ok(hunk.newExtent);
+  })
+
   it('honors the mergeAdjacentHunks option set to true', function () {
     const patch = new Patch({ mergeAdjacentHunks: true })