perf: make the most of streamed rendering

src/emitters/emitter.ts

@@ -1,4 +1,11 @@
 export interface Emitter {
+  /**
+   * Write a html value into emitter
+   * @param html string, Drop or other primitive value
+   */
   write (html: any): void;
-  end (): void;
+  /**
+   * Buffered string
+   */
+  buffer: string;
 }

src/emitters/keeping-type-emitter.ts

@@ -1,7 +1,8 @@
 import { stringify, toValue } from '../util/underscore'
+import { Emitter } from '../types'
 
-export class KeepingTypeEmitter {
-  public html: any = '';
+export class KeepingTypeEmitter implements Emitter {
+  public buffer: any = '';
 
   public write (html: any) {
     html = toValue(html)
@@ -9,14 +10,10 @@ export class KeepingTypeEmitter {
     // I.E:
     // {{ my-port }} -> 42
     // {{ my-host }}:{{ my-port }} -> 'host:42'
-    if (typeof html !== 'string' && this.html === '') {
-      this.html = html
+    if (typeof html !== 'string' && this.buffer === '') {
+      this.buffer = html
     } else {
-      this.html = stringify(this.html) + stringify(html)
+      this.buffer = stringify(this.buffer) + stringify(html)
     }
   }
-
-  public end () {
-    return this.html
-  }
 }

src/emitters/simple-emitter.ts

@@ -2,13 +2,9 @@ import { stringify } from '../util/underscore'
 import { Emitter } from './emitter'
 
 export class SimpleEmitter implements Emitter {
-  public html: any = '';
+  public buffer = '';
 
   public write (html: any) {
-    this.html += stringify(html)
-  }
-
-  public end () {
-    return this.html
+    this.buffer += stringify(html)
   }
 }

src/emitters/streamed-emitter.ts

@@ -1,7 +1,7 @@
 import { stringify } from '../util/underscore'
 
 export class StreamedEmitter {
-  public html: any = '';
+  public buffer = '';
   public stream = new (require('stream').PassThrough)()
   public write (html: any) {
     this.stream.write(stringify(html))