Internal: Changed the way of data serialization.

src/dev-utils/enableenginedebug.js

@@ -427,7 +427,7 @@ function enableReplayerTools() {
 			this._appliedOperations = [];
 		}
 
-		this._appliedOperations.push( operation.toJSON() );
+		this._appliedOperations.push( operation );
 
 		return _modelApplyOperation.call( this, operation );
 	} );
@@ -455,7 +455,7 @@ function enableDocumentTools() {
 			this._operationLogs = [];
 		}
 
-		this._operationLogs.push( JSON.stringify( operation.toJSON() ) );
+		this._operationLogs.push( JSON.stringify( operation ) );
 
 		return _modelApplyOperation.call( this, operation );
 	} );

src/model/node.js

@@ -381,7 +381,11 @@ export default class Node {
 		const json = {};
 
 		if ( this._attrs.size ) {
-			json.attributes = [ ...this._attrs ];
+			json.attributes = Array.from( this._attrs ).reduce( ( result, attr ) => {
+				result[ attr[ 0 ] ] = attr[ 1 ];
+
+				return result;
+			}, {} );
 		}
 
 		return json;

src/model/operation/attributeoperation.js

@@ -107,6 +107,17 @@ export default class AttributeOperation extends Operation {
 		return new AttributeOperation( this.range, this.key, this.newValue, this.oldValue, this.baseVersion + 1 );
 	}
 
+	/**
+	 * @inheritDoc
+	 */
+	toJSON() {
+		const json = super.toJSON();
+
+		json.range = this.range.toJSON();
+
+		return json;
+	}
+
 	/**
 	 * @inheritDoc
 	 */

src/model/operation/detachoperation.js

@@ -53,6 +53,17 @@ export default class DetachOperation extends Operation {
 		return 'detach';
 	}
 
+	/**
+	 * @inheritDoc
+	 */
+	toJSON() {
+		const json = super.toJSON();
+
+		json.sourcePosition = this.sourcePosition.toJSON();
+
+		return json;
+	}
+
 	/**
 	 * @inheritDoc
 	 */

src/model/operation/insertoperation.js

@@ -128,6 +128,18 @@ export default class InsertOperation extends Operation {
 		_insert( this.position, originalNodes );
 	}
 
+	/**
+	 * @inheritDoc
+	 */
+	toJSON() {
+		const json = super.toJSON();
+
+		json.position = this.position.toJSON();
+		json.nodes = this.nodes.toJSON();
+
+		return json;
+	}
+
 	/**
 	 * @inheritDoc
 	 */

src/model/operation/markeroperation.js

@@ -109,6 +109,14 @@ export default class MarkerOperation extends Operation {
 	toJSON() {
 		const json = super.toJSON();
 
+		if ( this.oldRange ) {
+			json.oldRange = this.oldRange.toJSON();
+		}
+
+		if ( this.newRange ) {
+			json.newRange = this.newRange.toJSON();
+		}
+
 		delete json._markers;
 
 		return json;

src/model/operation/mergeoperation.js

@@ -152,6 +152,19 @@ export default class MergeOperation extends Operation {
 		_move( Range.createOn( mergedElement ), this.graveyardPosition );
 	}
 
+	/**
+	 * @inheritDoc
+	 */
+	toJSON() {
+		const json = super.toJSON();
+
+		json.sourcePosition = json.sourcePosition.toJSON();
+		json.targetPosition = json.targetPosition.toJSON();
+		json.graveyardPosition = json.graveyardPosition.toJSON();
+
+		return json;
+	}
+
 	/**
 	 * @inheritDoc
 	 */

src/model/operation/moveoperation.js

@@ -175,6 +175,18 @@ export default class MoveOperation extends Operation {
 		_move( Range.createFromPositionAndShift( this.sourcePosition, this.howMany ), this.targetPosition );
 	}
 
+	/**
+	 * @inheritDoc
+	 */
+	toJSON() {
+		const json = super.toJSON();
+
+		json.sourcePosition = this.sourcePosition.toJSON();
+		json.targetPosition = this.targetPosition.toJSON();
+
+		return json;
+	}
+
 	/**
 	 * @inheritDoc
 	 */

src/model/operation/operation.js

@@ -7,8 +7,6 @@
  * @module engine/model/operation/operation
  */
 
-import { clone } from 'lodash-es';
-
 /**
  * Abstract base operation class.
  *
@@ -94,7 +92,9 @@ export default class Operation {
 	 * @returns {Object} Clone of this object with the operation property replaced with string.
 	 */
 	toJSON() {
-		const json = clone( this, true );
+		// This method creates only a shallow copy, all nested objects should be defined separately.
+		// See https://github.com/ckeditor/ckeditor5-engine/issues/1477.
+		const json = Object.assign( {}, this );
 
 		json.__className = this.constructor.className;
 

src/model/operation/renameoperation.js

@@ -116,6 +116,17 @@ export default class RenameOperation extends Operation {
 		element.name = this.newName;
 	}
 
+	/**
+	 * @inheritDoc
+	 */
+	toJSON() {
+		const json = super.toJSON();
+
+		json.position = this.position.toJSON();
+
+		return json;
+	}
+
 	/**
 	 * @inheritDoc
 	 */

src/model/operation/rootattributeoperation.js

@@ -162,6 +162,17 @@ export default class RootAttributeOperation extends Operation {
 		}
 	}
 
+	/**
+	 * @inheritDoc
+	 */
+	toJSON() {
+		const json = super.toJSON();
+
+		json.root = this.root.toJSON();
+
+		return json;
+	}
+
 	/**
 	 * @inheritDoc
 	 */
@@ -186,7 +197,7 @@ export default class RootAttributeOperation extends Operation {
 			 */
 			throw new CKEditorError(
 				'rootattribute-operation-fromjson-no-root: Cannot create RootAttributeOperation. Root with specified name does not exist.',
-				{ rootName: json }
+				{ rootName: json.root }
 			);
 		}
 

src/model/operation/splitoperation.js

@@ -166,6 +166,21 @@ export default class SplitOperation extends Operation {
 		_move( sourceRange, this.moveTargetPosition );
 	}
 
+	/**
+	 * @inheritDoc
+	 */
+	toJSON() {
+		const json = super.toJSON();
+
+		json.position = this.position.toJSON();
+
+		if ( this.graveyardPosition ) {
+			json.graveyardPosition = this.graveyardPosition.toJSON();
+		}
+
+		return json;
+	}
+
 	/**
 	 * @inheritDoc
 	 */

src/model/operation/unwrapoperation.js

@@ -130,6 +130,18 @@ export default class UnwrapOperation extends Operation {
 		_move( Range.createOn( elementToUnwrap ), this.graveyardPosition );
 	}
 
+	/**
+	 * @inheritDoc
+	 */
+	toJSON() {
+		const json = super.toJSON();
+
+		json.position = this.position.toJSON();
+		json.graveyardPosition = this.graveyardPosition.toJSON();
+
+		return json;
+	}
+
 	/**
 	 * @inheritDoc
 	 */

src/model/operation/wrapoperation.js

@@ -163,6 +163,21 @@ export default class WrapOperation extends Operation {
 		_move( wrappedRange, targetPosition );
 	}
 
+	/**
+	 * @inheritDoc
+	 */
+	toJSON() {
+		const json = super.toJSON();
+
+		json.position = this.position.toJSON();
+
+		if ( json.graveyardPosition ) {
+			json.graveyardPosition = this.graveyardPosition.toJSON();
+		}
+
+		return json;
+	}
+
 	/**
 	 * @inheritDoc
 	 */

src/model/position.js

@@ -790,6 +790,17 @@ export default class Position {
 		return combined;
 	}
 
+	/**
+	 * @inheritDoc
+	 */
+	toJSON() {
+		return {
+			root: this.root.toJSON(),
+			path: Array.from( this.path ),
+			stickiness: this.stickiness
+		};
+	}
+
 	/**
 	 * Creates position at the given location. The location can be specified as:
 	 *
@@ -915,7 +926,7 @@ export default class Position {
 	 */
 	static fromJSON( json, doc ) {
 		if ( json.root === '$graveyard' ) {
-			const pos = new Position( doc.graveyard, json.path );
+			const pos = new Position( doc.graveyard, Array.from( json.path ) );
 			pos.stickiness = json.stickiness;
 
 			return pos;
@@ -934,7 +945,7 @@ export default class Position {
 			);
 		}
 
-		const pos = new Position( doc.getRoot( json.root ), json.path );
+		const pos = new Position( doc.getRoot( json.root ), Array.from( json.path ) );
 		pos.stickiness = json.stickiness;
 
 		return pos;

src/model/range.js

@@ -469,6 +469,18 @@ export default class Range {
 		return this.start.getCommonAncestor( this.end );
 	}
 
+	/**
+	 * Converts `Range` to plain object and returns it.
+	 *
+	 * @returns {Object} `Node` converted to plain object.
+	 */
+	toJSON() {
+		return {
+			start: this.start.toJSON(),
+			end: this.end.toJSON()
+		};
+	}
+
 	_getTransformedByInsertOperation( operation, spread = false ) {
 		return this._getTransformedByInsertion( operation.position, operation.howMany, spread );
 	}

tests/dev-utils/enableenginedebug.js

@@ -644,7 +644,7 @@ describe( 'debug tools', () => {
 
 			const stringifiedOperations = model.getAppliedOperations();
 
-			expect( stringifiedOperations ).to.equal( JSON.stringify( insert.toJSON() ) );
+			expect( stringifiedOperations ).to.equal( JSON.stringify( insert ) );
 		} );
 
 		it( 'createReplayer()', () => {

tests/model/_utils/utils.js

@@ -36,15 +36,6 @@ export function getNodesAndText( range ) {
 	return txt;
 }
 
-/**
- * Returns object JSON representation. It passes an object by JSON.stringify and JSON.parse functions.
- *
- * @param {Object|Array} object
- */
-export function jsonParseStringify( object ) {
-	return JSON.parse( JSON.stringify( object ) );
-}
-
 /**
  * Returns a {@link engine.model.Node} or if it starts at given offset, or {@link engine.model.TextProxy} with one
  * character, if given offset is occupied by a {@link engine.model.Text}.

tests/model/document.js

@@ -12,7 +12,6 @@ import Range from '../../src/model/range';
 import Collection from '@ckeditor/ckeditor5-utils/src/collection';
 import CKEditorError from '@ckeditor/ckeditor5-utils/src/ckeditorerror';
 import count from '@ckeditor/ckeditor5-utils/src/count';
-import { jsonParseStringify } from './_utils/utils';
 
 describe( 'Document', () => {
 	let model, doc;
@@ -500,7 +499,7 @@ describe( 'Document', () => {
 	} );
 
 	it( 'should be correctly converted to json', () => {
-		const serialized = jsonParseStringify( doc );
+		const serialized = doc.toJSON();
 
 		expect( serialized.selection ).to.equal( '[engine.model.DocumentSelection]' );
 		expect( serialized.model ).to.equal( '[engine.model.Model]' );