feat: renderFileToNodeStream(filepath, scope)

src/emitters/streamed-emitter.ts

@@ -1,11 +1,15 @@
 import { stringify } from '../util/underscore'
+import { Emitter } from './emitter'
 
-export class StreamedEmitter {
+export class StreamedEmitter implements Emitter {
   public buffer = '';
-  public stream = new (require('stream').PassThrough)()
+  public stream: NodeJS.ReadWriteStream = new (require('stream').PassThrough)()
   public write (html: any) {
     this.stream.write(stringify(html))
   }
+  public error (err: Error) {
+    this.stream.emit('error', err)
+  }
   public end () {
     this.stream.end()
   }

src/liquid.ts

@@ -84,6 +84,10 @@ export class Liquid {
     const templates = this.parseFileSync(file)
     return this.renderSync(templates, ctx)
   }
+  public async renderFileToNodeStream (file: string, scope?: object) {
+    const templates = await this.parseFile(file)
+    return this.renderToNodeStream(templates, scope)
+  }
 
   public _evalValue (str: string, ctx: Context): IterableIterator<any> {
     const value = new Value(str, this)

src/render/render.ts

@@ -10,7 +10,8 @@ import { KeepingTypeEmitter } from '../emitters/keeping-type-emitter'
 export class Render {
   public renderTemplatesToNodeStream (templates: Template[], ctx: Context): NodeJS.ReadableStream {
     const emitter = new StreamedEmitter()
-    toThenable(this.renderTemplates(templates, ctx, emitter)).then(() => emitter.end())
+    toThenable(this.renderTemplates(templates, ctx, emitter))
+      .then(() => emitter.end(), err => emitter.error(err))
     return emitter.stream
   }
   public * renderTemplates (templates: Template[], ctx: Context, emitter?: Emitter): IterableIterator<any> {