feat: support {{block.super}}, see #38

src/builtin/tags/block.ts

@@ -1,8 +1,9 @@
 import BlockMode from '../../context/block-mode'
-import { ParseStream, TagToken, TopLevelToken, Template, Context, TagImplOptions, Emitter } from '../../types'
+import { BlockDrop } from '../../drop/block-drop'
+import { ParseStream, TagToken, TopLevelToken, Template, Context, TagImpl, Emitter } from '../../types'
 
 export default {
-  parse: function (token: TagToken, remainTokens: TopLevelToken[]) {
+  parse (this: TagImpl, token: TagToken, remainTokens: TopLevelToken[]) {
     const match = /\w+/.exec(token.args)
     this.block = match ? match[0] : ''
     this.tpls = [] as Template[]
@@ -14,18 +15,31 @@ export default {
       })
     stream.start()
   },
-  render: function * (ctx: Context, emitter: Emitter) {
-    const blocks = ctx.getRegister('blocks')
-    const childDefined = blocks[this.block]
-    const r = this.liquid.renderer
-    const html = childDefined !== undefined
-      ? childDefined
-      : yield r.renderTemplates(this.tpls, ctx)
 
+  * render (this: TagImpl, ctx: Context, emitter: Emitter) {
+    const blockRender = this.getBlockRender(ctx)
+    yield this.emitHTML(ctx, emitter, blockRender)
+  },
+
+  getBlockRender (this: TagImpl, ctx: Context) {
+    const { liquid, tpls } = this
+    const extendedBlockRender = ctx.getRegister('blocks')[this.block]
+    const defaultBlockRender = function * (superBlock: BlockDrop) {
+      ctx.push({ block: superBlock })
+      const result = yield liquid.renderer.renderTemplates(tpls, ctx)
+      ctx.pop()
+      return result
+    }
+    return extendedBlockRender
+      ? (superBlock: BlockDrop) => extendedBlockRender(new BlockDrop(() => defaultBlockRender(superBlock)))
+      : defaultBlockRender
+  },
+
+  * emitHTML (this: TagImpl, ctx: Context, emitter: Emitter, blockRender: (block: BlockDrop) => string) {
     if (ctx.getRegister('blockMode', BlockMode.OUTPUT) === BlockMode.STORE) {
-      blocks[this.block] = html
-      return
+      ctx.getRegister('blocks')[this.block] = blockRender
+    } else {
+      emitter.write(yield blockRender(new BlockDrop()))
     }
-    emitter.write(html)
   }
-} as TagImplOptions
+}

src/builtin/tags/layout.ts

@@ -20,15 +20,17 @@ export default {
         : evalToken(this.file, ctx))
       : file.getText()
     assert(filepath, () => `illegal filename "${file.getText()}":"${filepath}"`)
+    const templates = yield liquid._parseFile(filepath, ctx.opts, ctx.sync)
 
-    // render the remaining tokens immediately
+    // render remaining contents and store rendered results
     ctx.setRegister('blockMode', BlockMode.STORE)
-    const blocks = ctx.getRegister('blocks')
     const html = yield renderer.renderTemplates(this.tpls, ctx)
-    if (blocks[''] === undefined) blocks[''] = html
-    const templates = yield liquid._parseFile(filepath, ctx.opts, ctx.sync)
-    ctx.push(yield hash.render(ctx))
+    const blocks = ctx.getRegister('blocks')
+    if (blocks[''] === undefined) blocks[''] = () => html
     ctx.setRegister('blockMode', BlockMode.OUTPUT)
+
+    // render the layout file use stored blocks
+    ctx.push(yield hash.render(ctx))
     const partial = yield renderer.renderTemplates(templates, ctx)
     ctx.pop()
     emitter.write(partial)

src/drop/block-drop.ts

@@ -0,0 +1,13 @@
+import { Drop } from './drop'
+
+export class BlockDrop extends Drop {
+  constructor (
+    // the block render from layout template
+    private superBlockRender: () => Iterable<string> = () => ''
+  ) {
+    super()
+  }
+  public super () {
+    return this.superBlockRender()
+  }
+}

src/types.ts

@@ -11,6 +11,7 @@ export { Context } from './context/context'
 export { Template } from './template/template'
 export { FilterImplOptions } from './template/filter/filter-impl-options'
 export { TagImplOptions } from './template/tag/tag-impl-options'
+export { TagImpl } from './template/tag/tag-impl'
 export { ParseStream } from './parser/parse-stream'
 export { Token } from './tokens/token'
 export { TopLevelToken } from './tokens/toplevel-token'

test/integration/builtin/tags/layout.ts

@@ -69,6 +69,36 @@ describe('tags/layout', function () {
     const html = await liquid.parseAndRender(src)
     return expect(html).to.equal('XAYBZ')
   })
+  it('should support block.super', async function () {
+    mock({
+      '/parent.html': '{% block css %}<link href="base.css" rel="stylesheet">{% endblock %}'
+    })
+    const src = '{% layout "parent.html" %}' +
+      '{%block css%}{{block.super}}<link href="extra.css" rel="stylesheet">{%endblock%}'
+    const html = await liquid.parseAndRender(src)
+    const output = '<link href="base.css" rel="stylesheet"><link href="extra.css" rel="stylesheet">'
+    return expect(html).to.equal(output)
+  })
+  it('should render block.super to empty if no parent exists', async function () {
+    mock({
+      '/parent.html': '{% block css %}{{block.super}}<link href="base.css" rel="stylesheet">{% endblock %}'
+    })
+    const src = '{% layout "parent.html" %}' +
+      '{%block css%}{{block.super}}<link href="extra.css" rel="stylesheet">{%endblock%}'
+    const html = await liquid.parseAndRender(src)
+    const output = '<link href="base.css" rel="stylesheet"><link href="extra.css" rel="stylesheet">'
+    return expect(html).to.equal(output)
+  })
+  it('should support nested block.super', async function () {
+    mock({
+      '/root.html': '{% block css %}<link href="root.css" rel="stylesheet">{% endblock %}',
+      '/parent.html': '{% layout "root.html" %}{% block css %}{{block.super}}<link href="parent.css" rel="stylesheet">{% endblock %}'
+    })
+    const src = '{% layout "parent.html" %}{%block css%}{{block.super}}<link href="extra.css" rel="stylesheet">{%endblock%}'
+    const html = await liquid.parseAndRender(src)
+    const output = '<link href="root.css" rel="stylesheet"><link href="parent.css" rel="stylesheet"><link href="extra.css" rel="stylesheet">'
+    return expect(html).to.equal(output)
+  })
   it('should support variable as layout name', async function () {
     mock({
       '/parent.html': 'X{% block "a"%}{% endblock %}Y'