diff --git a/core/editor.js b/core/editor.js
index 8c4a42ee99..a25dcfcaa8 100644
--- a/core/editor.js
+++ b/core/editor.js
@@ -4,6 +4,7 @@ import extend from 'extend';
 import Delta from 'quill-delta';
 import DeltaOp from 'quill-delta/lib/op';
 import { LeafBlot } from 'parchment';
+import { Range } from './selection';
 import CursorBlot from '../blots/cursor';
 import Block, { bubbleFormats } from '../blots/block';
 import Break from '../blots/break';
@@ -204,14 +205,8 @@ class Editor {
       const oldText = new Delta().insert(oldValue);
       const newText = new Delta().insert(textBlot.value());
       const relativeSelectionInfo = selectionInfo && [
-        {
-          index: selectionInfo[0].index - index,
-          length: selectionInfo[0].length,
-        },
-        {
-          index: selectionInfo[1].index - index,
-          length: selectionInfo[1].length,
-        },
+        new Range(selectionInfo[0].index - index, selectionInfo[0].length),
+        new Range(selectionInfo[1].index - index, selectionInfo[1].length),
       ];
       const diffDelta = new Delta()
         .retain(index)
@@ -343,74 +338,74 @@ function splitDelta(delta, index) {
 }
 
 function diffDeltas(oldDelta, newDelta, selectionInfo = undefined) {
-  if (selectionInfo) {
-    // generate better diffs than Delta#diff by taking into account the
-    // old and new selection.  for example, a text change from "xxx" to "xx"
-    // could be a delete or forwards-delete of any one of the x's, or the
-    // result of selecting two of the x's and typing "x".
-    const [oldSelection, newSelection] = selectionInfo;
-    const oldDeltaLength = oldDelta.length();
-    const newDeltaLength = newDelta.length();
-    if (oldSelection.length === 0 && newSelection.length === 0) {
-      const oldCursor = oldSelection.index;
-      const newCursor = newSelection.index;
-      const [oldBefore, oldAfter] = splitDelta(oldDelta, oldCursor);
-      const [newBefore, newAfter] = splitDelta(newDelta, newCursor);
-      if (equal(oldAfter, newAfter)) {
-        const prefixLength = Math.min(oldCursor, newCursor);
-        const [oldPrefix, oldMiddle] = splitDelta(oldBefore, prefixLength);
-        const [newPrefix, newMiddle] = splitDelta(newBefore, prefixLength);
-        if (equal(oldPrefix, newPrefix)) {
-          // insert or delete right before cursor
-          return new Delta()
-            .retain(prefixLength)
-            .concat(oldMiddle.diff(newMiddle));
-        }
-      } else if (equal(oldBefore, newBefore)) {
-        const suffixLength = Math.min(
-          oldDeltaLength - oldCursor,
-          newDeltaLength - newCursor,
-        );
-        const [oldMiddle, oldSuffix] = splitDelta(
-          oldAfter,
-          oldDeltaLength - oldCursor - suffixLength,
-        );
-        const [newMiddle, newSuffix] = splitDelta(
-          newAfter,
-          newDeltaLength - newCursor - suffixLength,
-        );
-        if (equal(oldSuffix, newSuffix)) {
-          // insert or delete right after cursor
-          return new Delta()
-            .retain(oldCursor)
-            .concat(oldMiddle.diff(newMiddle));
-        }
+  if (selectionInfo == null) {
+    return oldDelta.diff(newDelta);
+  }
+
+  // generate better diffs than Delta#diff by taking into account the
+  // old and new selection.  for example, a text change from "xxx" to "xx"
+  // could be a delete or forwards-delete of any one of the x's, or the
+  // result of selecting two of the x's and typing "x".
+  const [oldSelection, newSelection] = selectionInfo;
+  const oldDeltaLength = oldDelta.length();
+  const newDeltaLength = newDelta.length();
+  if (oldSelection.length === 0 && newSelection.length === 0) {
+    // see if we have an insert or delete before or after cursor
+    const oldCursor = oldSelection.index;
+    const newCursor = newSelection.index;
+    const [oldBefore, oldAfter] = splitDelta(oldDelta, oldCursor);
+    const [newBefore, newAfter] = splitDelta(newDelta, newCursor);
+    if (equal(oldAfter, newAfter)) {
+      const prefixLength = Math.min(oldCursor, newCursor);
+      const [oldPrefix, oldMiddle] = splitDelta(oldBefore, prefixLength);
+      const [newPrefix, newMiddle] = splitDelta(newBefore, prefixLength);
+      if (equal(oldPrefix, newPrefix)) {
+        // insert or delete right before cursor
+        return new Delta()
+          .retain(prefixLength)
+          .concat(oldMiddle.diff(newMiddle));
       }
-    } else if (oldSelection.length > 0 && newSelection.length === 0) {
-      // see if diff could be a splice of the old selection range
-      const oldPrefix = oldDelta.slice(0, oldSelection.index);
-      const oldSuffix = oldDelta.slice(
-        oldSelection.index + oldSelection.length,
+    } else if (equal(oldBefore, newBefore)) {
+      const suffixLength = Math.min(
+        oldDeltaLength - oldCursor,
+        newDeltaLength - newCursor,
       );
-      const prefixLength = oldPrefix.length();
-      const suffixLength = oldSuffix.length();
-      if (newDeltaLength >= prefixLength + suffixLength) {
-        const newPrefix = newDelta.slice(0, prefixLength);
-        const newSuffix = newDelta.slice(newDeltaLength - suffixLength);
-        if (equal(oldPrefix, newPrefix) && equal(oldSuffix, newSuffix)) {
-          const oldMiddle = oldDelta.slice(
-            prefixLength,
-            oldDeltaLength - suffixLength,
-          );
-          const newMiddle = newDelta.slice(
-            prefixLength,
-            newDeltaLength - suffixLength,
-          );
-          return new Delta()
-            .retain(prefixLength)
-            .concat(newMiddle)
-            .delete(oldMiddle.length());
-        }
+      const [oldMiddle, oldSuffix] = splitDelta(
+        oldAfter,
+        oldDeltaLength - oldCursor - suffixLength,
+      );
+      const [newMiddle, newSuffix] = splitDelta(
+        newAfter,
+        newDeltaLength - newCursor - suffixLength,
+      );
+      if (equal(oldSuffix, newSuffix)) {
+        // insert or delete right after cursor
+        return new Delta().retain(oldCursor).concat(oldMiddle.diff(newMiddle));
+      }
+    }
+  }
+  if (oldSelection.length > 0 && newSelection.length === 0) {
+    // see if diff could be a splice of the old selection range
+    const oldPrefix = oldDelta.slice(0, oldSelection.index);
+    const oldSuffix = oldDelta.slice(oldSelection.index + oldSelection.length);
+    const prefixLength = oldPrefix.length();
+    const suffixLength = oldSuffix.length();
+    if (newDeltaLength >= prefixLength + suffixLength) {
+      const newPrefix = newDelta.slice(0, prefixLength);
+      const newSuffix = newDelta.slice(newDeltaLength - suffixLength);
+      if (equal(oldPrefix, newPrefix) && equal(oldSuffix, newSuffix)) {
+        const oldMiddle = oldDelta.slice(
+          prefixLength,
+          oldDeltaLength - suffixLength,
+        );
+        const newMiddle = newDelta.slice(
+          prefixLength,
+          newDeltaLength - suffixLength,
+        );
+        return new Delta()
+          .retain(prefixLength)
+          .concat(newMiddle)
+          .delete(oldMiddle.length());
       }
     }
   }
diff --git a/test/unit/core/quill.js b/test/unit/core/quill.js
index 7530c0547f..c508599824 100644
--- a/test/unit/core/quill.js
+++ b/test/unit/core/quill.js
@@ -243,7 +243,7 @@ describe('Quill', function() {
     ) {
       return function(done) {
         this.quill.setText(`${oldText}\n`);
-        this.quill.setSelection(oldSelection); // number or {index, length}
+        this.quill.setSelection(oldSelection); // number or Range
         this.quill.update();
         const oldContents = this.quill.getContents();
         const textNode = this.container.firstChild.firstChild.firstChild;
@@ -345,7 +345,7 @@ describe('Quill', function() {
       'replace yay with y',
       editTest(
         'yay',
-        { index: 0, length: 3 },
+        new Range(0, 3),
         'y',
         1,
         new Delta().insert('y').delete(3),