diff --git a/src/cli/format.js b/src/cli/format.js
index 13aeca6f86a6..01806522fae9 100644
--- a/src/cli/format.js
+++ b/src/cli/format.js
@@ -16,9 +16,18 @@ const getOptionsForFile = require("./options/get-options-for-file.js");
 const isTTY = require("./is-tty.js");
 
 function diff(a, b) {
-  return require("diff").createTwoFilesPatch("", "", a, b, "", "", {
-    context: 2,
-  });
+  // Use `diff/lib/patch/create.js` instead of `diff` to reduce bundle size
+  return require("diff/lib/patch/create.js").createTwoFilesPatch(
+    "",
+    "",
+    a,
+    b,
+    "",
+    "",
+    {
+      context: 2,
+    }
+  );
 }
 
 function handleError(context, filename, error, printedFilename) {
diff --git a/src/main/core.js b/src/main/core.js
index 63c40594a9b9..07e40624f856 100644
--- a/src/main/core.js
+++ b/src/main/core.js
@@ -1,6 +1,7 @@
 "use strict";
 
-const diff = require("diff");
+// Use `diff/lib/diff/array.js` instead of `diff` to reduce bundle size
+const { diffArrays } = require("diff/lib/diff/array.js");
 
 const {
   printer: { printDocToString },
@@ -118,7 +119,7 @@ function coreFormat(originalText, opts, addAlignmentSize = 0) {
 
     const newCursorNodeCharArray = [...newCursorNodeText];
 
-    const cursorNodeDiff = diff.diffArrays(
+    const cursorNodeDiff = diffArrays(
       oldCursorNodeCharArray,
       newCursorNodeCharArray
     );