mina-loader: 为lang属性增加前置、主要、后置三个loader配置项

packages/mina-loader/lib/loaders/mina.js

@@ -36,9 +36,22 @@ const getLoaders = (loaderContext, tag, options, attributes = {}) => {
     return ''
   }
 
-  // append custom loader
-  let custom = lang
-    ? options.languages[lang] || `${lang}-loader`
+  const getCustomizedLoader = (lang, { loaders = {}, languages = {} }) => {
+    const beforeLoader = languages[`${lang}:before`]
+    const mainLoader =  languages[`${lang}:main`] || loaders[tag]
+    const afterLoader = languages[`${lang}:after`] || languages[lang]
+    const toArray = val => {
+      if (val === undefined || val === null || val === '') {
+        return []
+      }
+      return Array.isArray(val) ? val : [val]
+    }
+    return [...toArray(beforeLoader), ...toArray(mainLoader), ...toArray(afterLoader)]
+  }
+
+  // HACK: 一旦getLoaders函数内发生异常，测试代码没有显示任何异常，应该是在某个地方压制住了它。望改善！
+  let custom = lang 
+    ? (Object.keys(options.languages).length === 0 ? `${lang}-loader` : getCustomizedLoader(lang, options))
     : options.loaders[tag] || ''
   if (custom) {
     custom = helpers.stringifyLoaders(

packages/mina-loader/test/fixtures/lang/override-loader.mina

@@ -1,7 +1,7 @@
-<script lang="yellowify">
+<script lang="number">
 Page({
   onLoad () {
-    console.log('blue');
+    console.log(9);
   }
 })
 </script>

packages/mina-loader/test/helpers/loaders/number-add-one-loader.js

@@ -0,0 +1,7 @@
+/**
+ * 找出其中的所有数字，每个加上1.
+ */
+
+module.exports = function(source) {
+  return source.replace(/\d+/g, val => Number(val) + 1)
+}

packages/mina-loader/test/helpers/loaders/number-multiply-two-loader.js

@@ -0,0 +1,7 @@
+/**
+ * 找出其中的所有数字，每个乘以2.
+ */
+
+module.exports = function(source) {
+  return source.replace(/\d+/g, val => Number(val) * 2)
+}

packages/mina-loader/test/lang.js

@@ -68,7 +68,7 @@ test('use lang attribute with extra rules', async t => {
   }
 })
 
-test('use lang attribute should override loaders options', async t => {
+test('use lang before attribute should prepend loaders options', async t => {
   try {
     const { compile, mfs } = compiler({
       entry: './fixtures/lang/override-loader.mina',
@@ -83,42 +83,105 @@ test('use lang attribute should override loaders options', async t => {
               loader: require.resolve('..'),
               options: {
                 loaders: {
-                  script: 'babel-loader',
+                  script: './helpers/loaders/number-multiply-two-loader.js',
                 },
                 languages: {
-                  yellowify: './helpers/loaders/replace-blue-to-yellow',
+                  'number:before': './helpers/loaders/number-add-one-loader.js', // (9*2)+1
                 },
               },
             },
           },
         ],
       },
     })
-    const stats = await compile()
+    await compile()
 
     t.true(
       mfs
         .readFileSync('/fixtures/lang/override-loader.js', 'utf8')
-        .includes("console.log('yellow')")
+        .includes("console.log(19)")
     )
-    t.false(
+  } catch (error) {
+    console.error(error)
+  }
+})
+
+test('use lang after attribute should append loaders options', async t => {
+  try {
+    const { compile, mfs } = compiler({
+      entry: './fixtures/lang/override-loader.mina',
+      output: {
+        filename: 'fixtures/lang/override-loader.js',
+      },
+      module: {
+        rules: [
+          {
+            test: /\.mina$/,
+            use: {
+              loader: require.resolve('..'),
+              options: {
+                loaders: {
+                  script: './helpers/loaders/number-multiply-two-loader.js',
+                },
+                languages: {
+                  'number:after': './helpers/loaders/number-add-one-loader.js', // (9+1)*2
+                },
+              },
+            },
+          },
+        ],
+      },
+    })
+    await compile()
+
+    t.true(
       mfs
         .readFileSync('/fixtures/lang/override-loader.js', 'utf8')
-        .includes("console.log('blue')")
+        .includes("console.log(20)")
     )
+  } catch (error) {
+    console.error(error)
+  }
+})
+
+test('use lang main attribute should override loaders options', async t => {
+  try {
+    const { compile, mfs } = compiler({
+      entry: './fixtures/lang/override-loader.mina',
+      output: {
+        filename: 'fixtures/lang/override-loader.js',
+      },
+      module: {
+        rules: [
+          {
+            test: /\.mina$/,
+            use: {
+              loader: require.resolve('..'),
+              options: {
+                loaders: {
+                  script: './helpers/loaders/number-multiply-two-loader.js',
+                },
+                languages: {
+                  'number:main': './helpers/loaders/number-add-one-loader.js', // 9+1
+                },
+              },
+            },
+          },
+        ],
+      },
+    })
+    await compile()
 
     t.true(
       mfs
         .readFileSync('/fixtures/lang/override-loader.js', 'utf8')
-        .includes('onLoad () {')
+        .includes("console.log(10)")
     )
     t.false(
       mfs
         .readFileSync('/fixtures/lang/override-loader.js', 'utf8')
-        .includes('onLoad: function onLoad() {')
+        .includes("console.log(18)")
     )
-
-    t.pass()
   } catch (error) {
     console.error(error)
   }