From 94f550767171f9986b84825de1f6d01c9e690873 Mon Sep 17 00:00:00 2001
From: Richard Hansen <rhansen@rhansen.org>
Date: Sat, 2 Oct 2021 18:17:11 -0400
Subject: [PATCH] Changeset: Improve `copyOp()` API

Use `Object.assign()` to implement `copyOp()`, which simplifies the
code and provides a return value. Also make the second op optional.
---
 src/static/js/Changeset.js | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/src/static/js/Changeset.js b/src/static/js/Changeset.js
index 9dc101701..4d3c30db5 100644
--- a/src/static/js/Changeset.js
+++ b/src/static/js/Changeset.js
@@ -205,14 +205,10 @@ exports.newOp = (optOpcode) => ({
  * Copies op1 to op2
  *
  * @param {Op} op1 - src Op
- * @param {Op} op2 - dest Op
+ * @param {Op} [op2] - dest Op. If not given, a new Op is used.
+ * @returns {Op} `op2`
  */
-const copyOp = (op1, op2) => {
-  op2.opcode = op1.opcode;
-  op2.chars = op1.chars;
-  op2.lines = op1.lines;
-  op2.attribs = op1.attribs;
-};
+const copyOp = (op1, op2 = exports.newOp()) => Object.assign(op2, op1);
 
 /**
  * Serializes a sequence of Ops.