refactor: add emitter for code generation

src/render/emitter.ts

@@ -0,0 +1,7 @@
+export class Emitter {
+  public html: string = '';
+
+  public write (html: string) {
+    this.html += html
+  }
+}

src/render/render.ts

@@ -2,23 +2,24 @@ import { RenderError } from '../util/error'
 import assert from '../util/assert'
 import Context from '../context/context'
 import ITemplate from '../template/itemplate'
+import { Emitter } from './emitter'
 
 export default class Render {
   public async renderTemplates (templates: ITemplate[], ctx: Context) {
     assert(ctx, 'unable to evalTemplates: context undefined')
 
-    let html = ''
+    const emitter = new Emitter()
     for (const tpl of templates) {
       try {
-        html += await tpl.render(ctx)
+        emitter.write(await tpl.render(ctx, emitter))
       } catch (e) {
         if (e.name === 'RenderBreakError') {
-          e.resolvedHTML = html
+          e.resolvedHTML = emitter.html
           throw e
         }
         throw e.name === 'RenderError' ? e : new RenderError(e, tpl)
       }
     }
-    return html
+    return emitter.html
   }
 }

src/template/itemplate.ts

@@ -1,7 +1,8 @@
 import Context from '../context/context'
 import Token from '../parser/token'
+import { Emitter } from '../render/emitter'
 
 export default interface ITemplate {
   token: Token;
-  render(ctx: Context): Promise<string>;
+  render(ctx: Context, emitter: Emitter): Promise<string>;
 }

test/integration/builtin/tags/for.ts

@@ -113,13 +113,23 @@ describe('tags/for', function () {
     const html = await liquid.parseAndRender(src, ctx)
     return expect(html).to.equal('12345')
   })
-  it('should support for with break', async function () {
+  describe('break', function () {
-    const src = '{% for i in (one..5) %}' +
+    it('should support break', async function () {
-      '{% if i == 4 %}{% break %}{% endif %}' +
+      const src = '{% for i in (one..5) %}' +
-      '{{ i }}' +
+        '{% if i == 4 %}{% break %}{% endif %}' +
-      '{% endfor %}'
+        '{{ i }}' +
-    const html = await liquid.parseAndRender(src, ctx)
+        '{% endfor %}'
-    return expect(html).to.equal('123')
+      const html = await liquid.parseAndRender(src, ctx)
+      return expect(html).to.equal('123')
+    })
+    it('should output contents before break', async function () {
+      const src = '{% for i in (1..5) %}' +
+        '{% if i == 4 %}breaking{% break %}{% endif %}' +
+        '{{ i }}' +
+        '{% endfor %}'
+      const html = await liquid.parseAndRender(src, ctx)
+      return expect(html).to.equal('123breaking')
+    })
   })
 
   describe('limit', function () {