Allow projects to save other types in variables

src/engine/runtime.js

@@ -464,6 +464,13 @@ class Runtime extends EventEmitter {
             warpTimer: false
         };
 
+        this.serializationOptions = {
+            /**
+             * Allows variables to be saved with types other than strings, numbers, and booleans.
+             */
+            ignoreVariableSerialization: false
+        };
+
         this.debug = false;
 
         this._lastStepTime = Date.now();

src/serialization/sb3.js

@@ -484,7 +484,8 @@ const serializeSound = function (sound) {
 // Using some bugs, it can be possible to get values like undefined, null, or complex objects into
 // variables or lists. This will cause make the project unusable after exporting without JSON editing
 // as it will fail validation in scratch-parser.
-// To avoid this, we'll convert those objects to strings before saving them.
+// To avoid this, we'll convert those objects to strings before saving them by default.
+// If the project goes against this (for certain extensions), dont bother doing this step.
 const isVariableValueSafeForJSON = value => (
     typeof value === 'number' ||
     typeof value === 'string' ||
@@ -516,11 +517,12 @@ const makeSafeForJSON = value => {
 /**
  * Serialize the given variables object.
  * @param {object} variables The variables to be serialized.
+ * @param {boolean} optIgnoreVarTypes If true, will ignore variable type serialization
  * @return {object} A serialized representation of the variables. They get
  * separated by type to compress the representation of each given variable and
  * reduce duplicate information.
  */
-const serializeVariables = function (variables) {
+const serializeVariables = function (variables, optIgnoreVarTypes) {
     const obj = Object.create(null);
     // separate out variables into types at the top level so we don't have
     // keep track of a type for each
@@ -534,12 +536,18 @@ const serializeVariables = function (variables) {
             continue;
         }
         if (v.type === Variable.LIST_TYPE) {
-            obj.lists[varId] = [v.name, makeSafeForJSON(v.value)];
+            obj.lists[varId] = [
+                v.name,
+                optIgnoreVarTypes ? v.value : makeSafeForJSON(v.value)
+            ];
             continue;
         }
 
         // otherwise should be a scalar type
-        obj.variables[varId] = [v.name, makeSafeForJSON(v.value)];
+        obj.variables[varId] = [
+            v.name,
+            optIgnoreVarTypes ? v.value : makeSafeForJSON(v.value)
+        ];
         // only scalar vars have the potential to be cloud vars
         if (v.isCloud) obj.variables[varId].push(true);
     }
@@ -580,14 +588,15 @@ const serializeComments = function (comments) {
  * for saving and loading this target.
  * @param {object} target The target to be serialized.
  * @param {Set} extensions A set of extensions to add extension IDs to
+ * @param {boolean} optIgnoreVarTypes If true, will ignore variable type serialization
  * @return {object} A serialized representation of the given target.
  */
-const serializeTarget = function (target, extensions) {
+const serializeTarget = function (target, extensions, optIgnoreVarTypes) {
     const obj = Object.create(null);
     let targetExtensions = [];
     obj.isStage = target.isStage;
     obj.name = obj.isStage ? 'Stage' : target.name;
-    const vars = serializeVariables(target.variables);
+    const vars = serializeVariables(target.variables, optIgnoreVarTypes);
     obj.variables = vars.variables;
     obj.lists = vars.lists;
     obj.broadcasts = vars.broadcasts;
@@ -730,7 +739,12 @@ const serialize = function (runtime, targetId, {allowOptimization = true} = {})
         });
     }
 
-    const serializedTargets = flattenedOriginalTargets.map(t => serializeTarget(t, extensions))
+    const serializationOptions = runtime.serializationOptions;
+    const serializedTargets = flattenedOriginalTargets.map(t => serializeTarget(
+        t,
+        extensions,
+        serializationOptions.ignoreVariableSerialization
+    ))
         .map((serialized, index) => {
             // can't serialize extensionStorage until the list of used extensions is fully known
             const target = originalTargetsToSerialize[index];