refactor: return value of Tag#render is no longer used

BREAKING CHANGE: Tag#render now returns void, use emitter argument
to write rendered html.

src/builtin/tags/block.ts

@@ -1,10 +1,5 @@
 import BlockMode from '../../context/block-mode'
-import { TagToken } from '../../parser/tag-token'
-import { Token } from '../../parser/token'
-import { ITemplate } from '../../template/itemplate'
-import { Context } from '../../context/context'
-import { ITagImplOptions } from '../../template/tag/itag-impl-options'
-import { ParseStream } from '../../parser/parse-stream'
+import { ParseStream, TagToken, Token, ITemplate, Context, ITagImplOptions, Emitter, Hash } from '../../types'
 
 export default {
   parse: function (token: TagToken, remainTokens: Token[]) {
@@ -19,7 +14,7 @@ export default {
       })
     stream.start()
   },
-  render: async function (ctx: Context) {
+  render: async function (ctx: Context, hash: Hash, emitter: Emitter) {
     const blocks = ctx.getRegister('blocks')
     const childDefined = blocks[this.block]
     const html = childDefined !== undefined
@@ -28,8 +23,8 @@ export default {
 
     if (ctx.getRegister('blockMode', BlockMode.OUTPUT) === BlockMode.STORE) {
       blocks[this.block] = html
-      return ''
+      return
     }
-    return html
+    emitter.write(html)
   }
 } as ITagImplOptions

src/builtin/tags/cycle.ts

@@ -1,9 +1,6 @@
 import { assert } from '../../util/assert'
 import { value as rValue } from '../../parser/lexical'
-import { Expression } from '../../render/expression'
-import { TagToken } from '../../parser/tag-token'
-import { Context } from '../../context/context'
-import { ITagImplOptions } from '../../template/tag/itag-impl-options'
+import { Emitter, Expression, TagToken, Context, ITagImplOptions, Hash } from '../../types'
 
 const groupRE = new RegExp(`^(?:(${rValue.source})\\s*:\\s*)?(.*)$`)
 const candidatesRE = new RegExp(rValue.source, 'g')
@@ -24,7 +21,7 @@ export default {
     assert(this.candidates.length, `empty candidates: ${tagToken.raw}`)
   },
 
-  render: async function (ctx: Context) {
+  render: async function (ctx: Context, hash: Hash, emitter: Emitter) {
     const group = this.group.value(ctx)
     const fingerprint = `cycle:${group}:` + this.candidates.join(',')
     const groups = ctx.getRegister('cycle')
@@ -37,7 +34,6 @@ export default {
     const candidate = this.candidates[idx]
     idx = (idx + 1) % this.candidates.length
     groups[fingerprint] = idx
-
-    return new Expression(candidate).value(ctx)
+    emitter.write(new Expression(candidate).value(ctx))
   }
 } as ITagImplOptions

src/builtin/tags/decrement.ts

@@ -1,9 +1,7 @@
 import { assert } from '../../util/assert'
 import { identifier } from '../../parser/lexical'
-import { TagToken } from '../../parser/tag-token'
-import { Context } from '../../context/context'
-import { ITagImplOptions } from '../../template/tag/itag-impl-options'
-import { isNumber } from '../../util/underscore'
+import { Emitter, TagToken, Context, ITagImplOptions, Hash } from '../../types'
+import { isNumber, stringify } from '../../util/underscore'
 
 export default {
   parse: function (token: TagToken) {
@@ -11,11 +9,11 @@ export default {
     assert(match, `illegal identifier ${token.args}`)
     this.variable = match[0]
   },
-  render: function (context: Context) {
+  render: function (context: Context, hash: Hash, emitter: Emitter) {
     const scope = context.environments
     if (!isNumber(scope[this.variable])) {
       scope[this.variable] = 0
     }
-    return --scope[this.variable]
+    emitter.write(stringify(--scope[this.variable]))
   }
 } as ITagImplOptions

src/builtin/tags/for.ts

@@ -47,7 +47,8 @@ export default {
       }
     }
     if (!isArray(collection) || !collection.length) {
-      return this.liquid.renderer.renderTemplates(this.elseTemplates, ctx)
+      this.liquid.renderer.renderTemplates(this.elseTemplates, ctx, emitter)
+      return
     }
 
     const offset = hash.offset || 0

src/builtin/tags/increment.ts

@@ -1,21 +1,21 @@
 import { assert } from '../../util/assert'
 import { identifier } from '../../parser/lexical'
-import { isNumber } from '../../util/underscore'
-import { ITagImplOptions } from '../../template/tag/itag-impl-options'
+import { isNumber, stringify } from '../../util/underscore'
+import { Emitter, TagToken, Context, ITagImplOptions, Hash } from '../../types'
 
 export default {
-  parse: function (token) {
+  parse: function (token: TagToken) {
     const match = token.args.match(identifier)
     assert(match, `illegal identifier ${token.args}`)
     this.variable = match![0]
   },
-  render: function (context) {
+  render: function (context: Context, hash: Hash, emitter: Emitter) {
     const scope = context.environments
     if (!isNumber(scope[this.variable])) {
       scope[this.variable] = 0
     }
     const val = scope[this.variable]
     scope[this.variable]++
-    return val
+    emitter.write(stringify(val))
   }
 } as ITagImplOptions

src/builtin/tags/layout.ts

@@ -1,8 +1,7 @@
 import { assert } from '../../util/assert'
 import { value as rValue } from '../../parser/lexical'
-import { Expression, TagToken, Token, Context, ITagImplOptions } from '../../types'
+import { Emitter, Hash, Expression, TagToken, Token, Context, ITagImplOptions } from '../../types'
 import BlockMode from '../../context/block-mode'
-import { Hash } from '../../template/tag/hash'
 
 const staticFileRE = /\S+/
 
@@ -20,7 +19,7 @@ export default {
 
     this.tpls = this.liquid.parser.parse(remainTokens)
   },
-  render: async function (ctx: Context, hash: Hash) {
+  render: async function (ctx: Context, hash: Hash, emitter: Emitter) {
     const layout = ctx.opts.dynamicPartials
       ? await (new Expression(this.layout).value(ctx))
       : this.staticLayout
@@ -38,6 +37,6 @@ export default {
     ctx.setRegister('blockMode', BlockMode.OUTPUT)
     const partial = await this.liquid.renderer.renderTemplates(templates, ctx)
     ctx.pop()
-    return partial
+    emitter.write(partial)
   }
 } as ITagImplOptions

src/builtin/tags/raw.ts

@@ -1,4 +1,4 @@
-import { TagToken, Token, ITagImplOptions } from '../../types'
+import { TagToken, Token, ITagImplOptions, Context, Emitter, Hash } from '../../types'
 
 export default {
   parse: function (tagToken: TagToken, remainTokens: Token[]) {
@@ -15,7 +15,7 @@ export default {
       })
     stream.start()
   },
-  render: function () {
-    return this.tokens.map((token: Token) => token.raw).join('')
+  render: function (ctx: Context, hash: Hash, emitter: Emitter) {
+    emitter.write(this.tokens.map((token: Token) => token.raw).join(''))
   }
 } as ITagImplOptions

src/template/tag/tag.ts

@@ -1,4 +1,4 @@
-import { stringify, isFunction } from '../../util/underscore'
+import { isFunction } from '../../util/underscore'
 import { assert } from '../../util/assert'
 import { Liquid } from '../../liquid'
 import { Template } from '../../template/template'
@@ -26,8 +26,7 @@ export class Tag extends Template<TagToken> implements ITemplate {
   public async render (ctx: Context, emitter: Emitter) {
     const hash = await Hash.create(this.token.args, ctx)
     const impl = this.impl
-    const html = isFunction(impl.render) ? stringify(await impl.render(ctx, hash, emitter)) : ''
-    html && emitter.write(html)
+    if (isFunction(impl.render)) await impl.render(ctx, hash, emitter)
   }
   public static register (name: string, tag: ITagImplOptions) {
     Tag.impls[name] = tag