feat: add option for keeping variable type in output

src/render/emitter.ts

@@ -1,9 +1,18 @@
 export class Emitter {
-  public html = '';
+  public html: any = '';
   public break = false;
   public continue = false;
+  private keepOutputType? = false;
 
-  public write (html: string) {
-    this.html += html
+  constructor (keepOutputType: boolean|undefined) {
+    this.keepOutputType = keepOutputType
+  }
+
+  public write (html: any) {
+    if (this.keepOutputType && typeof html !== 'string') {
+      this.html = html
+    } else {
+      this.html += html as string
+    }
   }
 }

src/render/render.ts

@@ -4,7 +4,7 @@ import { Template } from '../template/template'
 import { Emitter } from './emitter'
 
 export class Render {
-  public * renderTemplates (templates: Template[], ctx: Context, emitter = new Emitter()): IterableIterator<string> {
+  public * renderTemplates (templates: Template[], ctx: Context, emitter: Emitter): IterableIterator<any> {
     for (const tpl of templates) {
       try {
         const html = yield tpl.render(ctx, emitter)