refactor: simplify plugin implementation

This also removes the need for ident reuse whitelist
and properly shares ident between original and cloned
rules.

Author: yyx990803

Diff for: lib/plugin.js

@@ -25,29 +25,16 @@ class VueLoaderPlugin {
       })
     }
 
-    // get a hold of the raw rules
-    const rawRules = compiler.options.module.rules.slice()
     // use webpack's RuleSet utility to normalize user rules
-    const rawNormalizedRules = new RuleSet(rawRules).rules
-
-    const createMatcher = fakeFile => (rule, i) => {
-      // #1201 we need to skip the `include` check when locating the vue rule
-      const clone = Object.assign({}, rule)
-      delete clone.include
-      const normalized = RuleSet.normalizeRule(clone, {}, '')
-      return (
-        !rule.enforce &&
-        normalized.resource &&
-        normalized.resource(fakeFile)
-      )
-    }
+    const rawRules = compiler.options.module.rules
+    const { rules } = new RuleSet(rawRules)
 
     // find the rule that applies to vue files
     let vueRuleIndex = rawRules.findIndex(createMatcher(`foo.vue`))
     if (vueRuleIndex < 0) {
       vueRuleIndex = rawRules.findIndex(createMatcher(`foo.vue.html`))
     }
-    const vueRule = rawRules[vueRuleIndex]
+    const vueRule = rules[vueRuleIndex]
 
     if (!vueRule) {
       throw new Error(
@@ -62,12 +49,10 @@ class VueLoaderPlugin {
       )
     }
 
-    // find the normalized version of the vue rule
-    const normalizedVueRule = rawNormalizedRules[vueRuleIndex]
     // get the normlized "use" for vue files
-    const normalizedVueUse = normalizedVueRule.use
+    const vueUse = vueRule.use
     // get vue-loader options
-    const vueLoaderUseIndex = normalizedVueUse.findIndex(u => {
+    const vueLoaderUseIndex = vueUse.findIndex(u => {
       return /^vue-loader|(\/|\\)vue-loader/.test(u.loader)
     })
 
@@ -81,76 +66,69 @@ class VueLoaderPlugin {
     // make sure vue-loader options has a known ident so that we can share
     // options by reference in the template-loader by using a ref query like
     // template-loader??vue-loader-options
-    const ident = 'vue-loader-options'
-    const vueLoaderUse = normalizedVueUse[vueLoaderUseIndex]
-    // has options, just set ident
-    if (vueLoaderUse.options) {
-      vueLoaderUse.options.ident = ident
-    } else {
-      // user provided no options, but we must ensure the options is present
-      // otherwise RuleSet throws error if no option for a given ref is found.
-      if (vueRule.loader || vueRule.loaders) {
-        vueRule.options = { ident }
-      } else if (Array.isArray(vueRule.use)) {
-        const use = vueRule.use[vueLoaderUseIndex]
-        if (typeof use === 'string') {
-          vueRule.use[vueLoaderUseIndex] = { loader: use, options: { ident }}
-        } else {
-          use.options = { ident }
-        }
-      } else if (typeof vueRule.use === 'string') {
-        vueRule.use = [{ loader: vueRule.use, options: { ident }}]
-      } else {
-        throw new Error(
-          `VueLoaderPlugin Error: this should not happen. Please open an issue ` +
-          `with your webpack config.`
-        )
-      }
-    }
-
-    // get new rules without the vue rule
-    const baseRules = rawRules.filter(r => r !== vueRule)
-    const normalizedRules = rawNormalizedRules.filter(r => r !== normalizedVueRule)
-
-    // for each user rule, inject a cloned rule by checking if the rule
-    // matches the lang specified in the resourceQuery.
-    rawRules.unshift.apply(rawRules, baseRules.map((rule, i) => {
-      return cloneRule(rule, normalizedRules[i])
-    }))
-
-    // inject global pitcher (responsible for injecting template compiler
-    // loader & CSS post loader)
-    rawRules.unshift({
+    const vueLoaderUse = vueUse[vueLoaderUseIndex]
+    vueLoaderUse.ident = 'vue-loader-options'
+    vueLoaderUse.options = vueLoaderUse.options || {}
+
+    // for each user rule (expect the vue rule), create a cloned rule
+    // that targets the corresponding language blocks in *.vue files.
+    const clonedRules = rules
+      .filter(r => r !== vueRule)
+      .map(cloneRule)
+
+    // global pitcher (responsible for injecting template compiler loader & CSS
+    // post loader)
+    const pitcher = {
       loader: require.resolve('./loaders/pitcher'),
       resourceQuery: query => {
         const parsed = qs.parse(query.slice(1))
         return parsed.vue != null
       }
-    })
+    }
 
     // replace original rules
-    compiler.options.module.rules = rawRules
+    compiler.options.module.rules = [
+      pitcher,
+      ...clonedRules,
+      ...rules
+    ]
+  }
+}
+
+function createMatcher (fakeFile) {
+  return (rule, i) => {
+    // #1201 we need to skip the `include` check when locating the vue rule
+    const clone = Object.assign({}, rule)
+    delete clone.include
+    const normalized = RuleSet.normalizeRule(clone, {}, '')
+    return (
+      !rule.enforce &&
+      normalized.resource &&
+      normalized.resource(fakeFile)
+    )
   }
 }
 
-function cloneRule (rule, normalizedRule) {
+function cloneRule (rule) {
+  const { resource, resourceQuery } = rule
   // Assuming `test` and `resourceQuery` tests are executed in series and
   // synchronously (which is true based on RuleSet's implementation), we can
   // save the current resource being matched from `test` so that we can access
   // it in `resourceQuery`. This ensures when we use the normalized rule's
   // resource check, include/exclude are matched correctly.
   let currentResource
   const res = Object.assign({}, rule, {
-    test: resource => {
-      currentResource = resource
-      return true
+    resource: {
+      test: resource => {
+        currentResource = resource
+        return true
+      }
     },
     resourceQuery: query => {
       const parsed = qs.parse(query.slice(1))
       if (parsed.vue == null) {
         return false
       }
-      const { resource, resourceQuery } = normalizedRule
       if (resource && parsed.lang == null) {
         return false
       }
@@ -162,50 +140,15 @@ function cloneRule (rule, normalizedRule) {
         return false
       }
       return true
-    },
-    use: normalizedRule.use ? normalizedRule.use.map(cleanIdent) : undefined
+    }
   })
 
-  // delete shorthand since we have normalized use
-  delete res.loader
-  delete res.loaders
-  delete res.options
-
-  // these are included in the normalized resource() check
-  delete res.resource
-  delete res.include
-  delete res.exclude
-
   if (rule.oneOf) {
-    res.oneOf = rule.oneOf.map((r, i) => {
-      return cloneRule(r, normalizedRule.oneOf[i])
-    })
+    res.oneOf = rule.oneOf.map(cloneRule)
   }
 
   return res
 }
 
-const reuseIdentWhitelist = [
-  'css-loader',
-  '(vue-)?style-loader',
-  'postcss-loader',
-  'extract-text-webpack-plugin',
-  'mini-css-extract-plugin'
-]
-
-const reuseIdentPattern = new RegExp(`(${reuseIdentWhitelist.join('|')})`)
-
-function cleanIdent (use) {
-  if (use.ident) {
-    if (reuseIdentPattern.test(use.loader)) {
-      // Reuse options ident, so that imports from within css-loader would get the
-      // exact same request prefixes, avoiding duplicated modules (#1199)
-      use.options.ident = use.ident
-    }
-    delete use.ident
-  }
-  return use
-}
-
 VueLoaderPlugin.NS = NS
 module.exports = VueLoaderPlugin