3 files changed, 40 insertions, 19 deletions

diff --git a/ext/js/templates/template-renderer-frame-api.js b/ext/js/templates/template-renderer-frame-api.js
index 4936a2af..6eebc199 100644
--- a/ext/js/templates/template-renderer-frame-api.js
+++ b/ext/js/templates/template-renderer-frame-api.js
@@ -19,7 +19,8 @@ class TemplateRendererFrameApi {
     constructor(templateRenderer) {
         this._templateRenderer = templateRenderer;
         this._windowMessageHandlers = new Map([
-            ['render', {async: true, handler: this._onRender.bind(this)}]
+            ['render', {async: true, handler: this._onRender.bind(this)}],
+            ['getModifiedData', {async: true, handler: this._onGetModifiedData.bind(this)}]
         ]);
     }
 
@@ -57,6 +58,11 @@ class TemplateRendererFrameApi {
         return await this._templateRenderer.render(template, data, type);
     }
 
+    async _onGetModifiedData({data, type}) {
+        const result = await this._templateRenderer.getModifiedData(data, type);
+        return this._clone(result);
+    }
+
     _errorToJson(error) {
         try {
             if (error !== null && typeof error === 'object') {
@@ -75,4 +81,8 @@ class TemplateRendererFrameApi {
             hasValue: true
         };
     }
+
+    _clone(value) {
+        return JSON.parse(JSON.stringify(value));
+    }
 }
diff --git a/ext/js/templates/template-renderer-proxy.js b/ext/js/templates/template-renderer-proxy.js
index 6a49832b..aba45e6c 100644
--- a/ext/js/templates/template-renderer-proxy.js
+++ b/ext/js/templates/template-renderer-proxy.js
@@ -30,6 +30,11 @@ class TemplateRendererProxy {
         return await this._invoke('render', {template, data, type});
     }
 
+    async getModifiedData(data, type) {
+        await this._prepareFrame();
+        return await this._invoke('getModifiedData', {data, type});
+    }
+
     // Private
 
     async _prepareFrame() {
diff --git a/ext/js/templates/template-renderer.js b/ext/js/templates/template-renderer.js
index f72740d5..a7a4a842 100644
--- a/ext/js/templates/template-renderer.js
+++ b/ext/js/templates/template-renderer.js
@@ -29,8 +29,8 @@ class TemplateRenderer {
         this._dataTypes = new Map();
     }
 
-    registerDataType(name, {modifier=null, modifierPost=null}) {
-        this._dataTypes.set(name, {modifier, modifierPost});
+    registerDataType(name, {modifier=null}) {
+        this._dataTypes.set(name, {modifier});
     }
 
     async render(template, data, type) {
@@ -47,32 +47,38 @@ class TemplateRenderer {
             cache.set(template, instance);
         }
 
-        let modifier = null;
-        let modifierPost = null;
-        if (typeof type === 'string') {
-            const typeInfo = this._dataTypes.get(type);
-            if (typeof typeInfo !== 'undefined') {
-                ({modifier, modifierPost} = typeInfo);
-            }
-        }
-
         try {
-            if (typeof modifier === 'function') {
-                data = modifier(data);
-            }
-
+            data = this._getModifiedData(data, type);
             this._stateStack = [new Map()];
             return instance(data).trim();
         } finally {
             this._stateStack = null;
+        }
+    }
 
-            if (typeof modifierPost === 'function') {
-                modifierPost(data);
+    async getModifiedData(data, type) {
+        return this._getModifiedData(data, type);
+    }
+
+    // Private
+
+    _getModifier(type) {
+        if (typeof type === 'string') {
+            const typeInfo = this._dataTypes.get(type);
+            if (typeof typeInfo !== 'undefined') {
+                return typeInfo.modifier;
             }
         }
+        return null;
     }
 
-    // Private
+    _getModifiedData(data, type) {
+        const modifier = this._getModifier(type);
+        if (typeof modifier === 'function') {
+            data = modifier(data);
+        }
+        return data;
+    }
 
     _updateCacheSize(maxSize) {
         const cache = this._cache;