From bc0e99ab4a79e562f2aacb8e300841e4620d116e Mon Sep 17 00:00:00 2001
From: jos <wjosdejong@gmail.com>
Date: Wed, 10 Jul 2019 14:27:46 +0200
Subject: [PATCH] Fixed #730: in `code` mode, there was an initial undo action
 which clears the content

---
 HISTORY.md         |  6 ++++++
 src/js/textmode.js | 26 +++++++++++++++++++++-----
 2 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/HISTORY.md b/HISTORY.md
index afd3ae0..5523aa0 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -3,6 +3,12 @@
 https://github.com/josdejong/jsoneditor
 
 
+## not yet published, version 6.1.1
+
+- Fixed #730: in `code` mode, there was an initial undo action which clears
+  the content.
+
+
 ## 2019-06-22, version 6.1.0
 
 - Implemented menu options `sort` and `transform` for modes `code` and `text`.
diff --git a/src/js/textmode.js b/src/js/textmode.js
index 934aa97..4556658 100644
--- a/src/js/textmode.js
+++ b/src/js/textmode.js
@@ -734,10 +734,12 @@ textmode.getText = function() {
 };
 
 /**
- * Set the text contents of the editor
+ * Set the text contents of the editor and optionally clear the history
  * @param {String} jsonText
+ * @param {boolean} clearHistory   Only applicable for mode 'code'
+ * @private
  */
-textmode.setText = function(jsonText) {
+textmode._setText = function(jsonText, clearHistory) {
   var text;
 
   if (this.options.escapeUnicode === true) {
@@ -756,12 +758,28 @@ textmode.setText = function(jsonText) {
 
     this.aceEditor.setValue(text, -1);
 
+    if (clearHistory) {
+      // prevent initial undo action clearing the initial contents
+      var me = this;
+      setTimeout(function () {
+        me.aceEditor.session.getUndoManager().reset();
+      }, 0);
+    }
+
     this.onChangeDisabled = false;
   }
   // validate JSON schema
   this._debouncedValidate();
 };
 
+/**
+ * Set the text contents of the editor
+ * @param {String} jsonText
+ */
+textmode.setText = function(jsonText) {
+  this._setText(jsonText, true)
+};
+
 /**
  * Update the text contents
  * @param {string} jsonText
@@ -772,9 +790,7 @@ textmode.updateText = function(jsonText) {
     return;
   }
 
-  this.onChangeDisabled = true; // don't fire an onChange event
-  this.setText(jsonText);
-  this.onChangeDisabled = false;
+  this._setText(jsonText, false);
 };
 
 /**