build: introduce feature flags, hide new slot syntax behind flag

scripts/config.js

@@ -7,6 +7,7 @@ const node = require('rollup-plugin-node-resolve')
 const flow = require('rollup-plugin-flow-no-whitespace')
 const version = process.env.VERSION || require('../package.json').version
 const weexVersion = process.env.WEEX_VERSION || require('../packages/weex-vue-framework/package.json').version
+const featureFlags = require('./feature-flags')
 
 const banner =
   '/*!\n' +
@@ -241,9 +242,13 @@ function genConfig (name) {
   }
 
   if (opts.env) {
-    config.plugins.push(replace({
+    const vars = {
       'process.env.NODE_ENV': JSON.stringify(opts.env)
-    }))
+    }
+    Object.keys(featureFlags).forEach(key => {
+      vars[`process.env.${key}`] = featureFlags[key]
+    })
+    config.plugins.push(replace(vars))
   }
 
   if (opts.transpile !== false) {

scripts/feature-flags.js

@@ -0,0 +1,3 @@
+module.exports = {
+  NEW_SLOT_SYNTAX: false
+}

src/compiler/parser/index.js

@@ -568,11 +568,12 @@ function processSlotContent (el) {
     }
     el.slotScope = (
       slotScope ||
-      getAndRemoveAttr(el, 'slot-scope') ||
+      getAndRemoveAttr(el, 'slot-scope')
+    )
+    if (process.env.NEW_SLOT_SYNTAX) {
       // new in 2.6: slot-props and its shorthand works the same as slot-scope
       // when used on <template> containers
-      getAndRemoveAttr(el, 'slot-props')
-    )
+      el.slotScope = el.slotScope || getAndRemoveAttr(el, 'slot-props')
       // 2.6 shorthand syntax
       const shorthand = getAndRemoveAttrByRegex(el, scopedSlotShorthandRE)
       if (shorthand) {
@@ -585,6 +586,7 @@ function processSlotContent (el) {
         el.slotTarget = getScopedSlotShorthandName(shorthand)
         el.slotScope = shorthand.value
       }
+    }
   } else if ((slotScope = getAndRemoveAttr(el, 'slot-scope'))) {
     /* istanbul ignore if */
     if (process.env.NODE_ENV !== 'production' && el.attrsMap['v-for']) {
@@ -597,7 +599,7 @@ function processSlotContent (el) {
       )
     }
     el.slotScope = slotScope
-  } else {
+  } else if (process.env.NEW_SLOT_SYNTAX) {
     // 2.6: slot-props on component, denotes default slot
     slotScope = getAndRemoveAttr(el, 'slot-props')
     const shorthand = getAndRemoveAttrByRegex(el, scopedSlotShorthandRE)

src/core/vdom/helpers/normalize-scoped-slots.js

@@ -32,7 +32,7 @@ export function normalizeScopedSlots (
 function normalizeScopedSlot(fn: Function): Function {
   return scope => {
     const res = fn(scope)
-    return res && typeof res === 'object'
+    return res && typeof res === 'object' && !Array.isArray(res)
       ? [res] // single vnode
       : normalizeChildren(res)
   }

test/unit/features/component/component-scoped-slot.spec.js

@@ -632,7 +632,8 @@ describe('Component scoped slot', () => {
     }).then(done)
   })
 
-  // new in 2.6
+  // 2.6 new slot syntax
+  if (process.env.NEW_SLOT_SYNTAX) {
     describe('slot-props syntax', () => {
       const Foo = {
         render(h) {
@@ -646,13 +647,13 @@ describe('Component scoped slot', () => {
 
       const Bar = {
         render(h) {
-        return this.$scopedSlots.default && this.$scopedSlots.default('from bar')[0]
+          return this.$scopedSlots.default && this.$scopedSlots.default('from bar')
         }
       }
 
       const Baz = {
         render(h) {
-        return this.$scopedSlots.default && this.$scopedSlots.default('from baz')[0]
+          return this.$scopedSlots.default && this.$scopedSlots.default('from baz')
         }
       }
 
@@ -792,4 +793,5 @@ describe('Component scoped slot', () => {
         expect(vm.$el.innerHTML.replace(/\s+/g, ' ')).toMatch(`from foo one from foo two`)
       })
     })
+  }
 })

test/unit/karma.base.config.js

@@ -1,4 +1,5 @@
 const alias = require('../../scripts/alias')
+const featureFlags = require('../../scripts/feature-flags')
 const webpack = require('webpack')
 
 const webpackConfig = {
@@ -20,7 +21,8 @@ const webpackConfig = {
       __WEEX__: false,
       'process.env': {
         TRANSITION_DURATION: process.env.CI ? 100 : 50,
-        TRANSITION_BUFFER: 10
+        TRANSITION_BUFFER: 10,
+        ...featureFlags
       }
     })
   ],