feat: add JSO serialization and deserialization of variables

core/requires.js

@@ -84,3 +84,4 @@ goog.require('Blockly.zelos.Renderer');
 goog.require('Blockly.Themes.Classic');
 
 goog.require('Blockly.serialization.blocks');
+goog.require('Blockly.serialization.variables');

core/serialization/variables.js

@@ -0,0 +1,62 @@
+/**
+ * @license
+ * Copyright 2021 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @fileoverview Handles serializing variables to plain JavaScript objects, only
+ *     containing state.
+ */
+'use strict';
+
+goog.module('Blockly.serialization.variables');
+goog.module.declareLegacyNamespace();
+
+// eslint-disable-next-line no-unused-vars
+const VariableModel = goog.requireType('Blockly.VariableModel');
+// eslint-disable-next-line no-unused-vars
+const Workspace = goog.requireType('Blockly.Workspace');
+
+
+/**
+ * Represents the state of a given variable.
+ * @typedef {{
+ *   name: string,
+ *   id: string,
+ *   type: (string|undefined),
+ * }}
+ */
+var State;
+exports.State = State;
+
+/**
+ * Returns the state of the variable as a plain JavaScript object.
+ * @param {!VariableModel} variableModel The variable to serialize.
+ * @return {!State} The serialized state of the variable.
+ */
+const save = function(variableModel) {
+  const state = {
+    'name': variableModel.name,
+    'id': variableModel.getId()
+  };
+  if (variableModel.type) {
+    state['type'] = variableModel.type;
+  }
+  return state;
+};
+/** @package */
+exports.save = save;
+
+/**
+ * Loads the variable represented by the given state into the given workspace.
+ * Do not call this directly, use workspace.createVariable instead.
+ * @param {!State} state The state of a variable to deserialize into the
+ *     workspace.
+ * @param {!Workspace} workspace The workspace to add the variable to.
+ */
+const load = function(state, workspace) {
+  workspace.createVariable(state['name'], state['type'], state['id']);
+};
+/** @package */
+exports.load = load;

tests/mocha/jso_serialization_test.js

@@ -21,15 +21,16 @@ suite('JSO', function() {
     sharedTestTeardown.call(this);
   });
 
-  suite('Blocks', function() {
-    function assertProperty(obj, property, value) {
-      chai.assert.deepEqual(obj[property], value);
-    }
+  function assertProperty(obj, property, value) {
+    chai.assert.deepEqual(obj[property], value);
+  }
+
+  function assertNoProperty(obj, property) {
+    assertProperty(obj, property, undefined);
+  }
 
-    function assertNoProperty(obj, property) {
-      assertProperty(obj, property, undefined);
-    }
 
+  suite('Blocks', function() {
     test('Null on insertionMarkers', function() {
       const block = this.workspace.newBlock('row_block');
       block.setInsertionMarker(true);
@@ -629,4 +630,23 @@ suite('JSO', function() {
       });
     });
   });
+
+  suite('Variables', function() {
+    test('Without type', function() {
+      const variable = this.workspace.createVariable('testVar', '', 'testId');
+      const jso = Blockly.serialization.variables.save(variable);
+      assertProperty(jso, 'name', 'testVar');
+      assertProperty(jso, 'id', 'testId');
+      assertNoProperty(jso, 'type');
+    });
+
+    test('With type', function() {
+      const variable = this.workspace
+          .createVariable('testVar', 'testType', 'testId');
+      const jso = Blockly.serialization.variables.save(variable);
+      assertProperty(jso, 'name', 'testVar');
+      assertProperty(jso, 'id', 'testId');
+      assertProperty(jso, 'type', 'testType');
+    });
+  });
 });