├─package-lock.json
├─package.json
├─src
|  ├─App.vue
|  └index.js
├─dist
|  └main.js
├─config
| ? └webpack.config.js

<template>
  <div id="box">
 ?  {{ count }}
  </div>
</template>
?
<script>
export default {
  props: {},
  data() {
 ?  return {
 ? ?  count: 0
 ?  }
  }
}
</script>
?
<style scoped>
#box {
  background: red;
}
</style>

const { VueLoaderPlugin } = require('vue-loader')
?
module.exports = {
  mode: 'development',
  module: {
 ?  rules: [
 ? ?  {
 ? ? ?  test: /.vue$/,
 ? ? ?  loader: 'vue-loader'
 ? ?  },
 ? ?  // 它會應(yīng)用到普通的 `.js` 文件
 ? ?  // 以及 `.vue` 文件中的 `<script>` 塊
 ? ?  {
 ? ? ?  test: /.js$/,
 ? ? ?  loader: 'babel-loader'
 ? ?  },
 ? ?  // 它會應(yīng)用到普通的 `.css` 文件
 ? ?  // 以及 `.vue` 文件中的 `<style>` 塊
 ? ?  {
 ? ? ?  test: /.css$/,
 ? ? ?  use: [
 ? ? ? ?  'vue-style-loader',
 ? ? ? ?  'css-loader'
 ? ? ?  ]
 ? ?  }
 ?  ]
  },
  plugins: [
 ?  new VueLoaderPlugin()
  ]
}

/***/ "./src/App.vue"
?
__webpack_require__.r(__webpack_exports__);
/* harmony export */ __webpack_require__.d(__webpack_exports__, {
  /* harmony export */ ? "default": () => (__WEBPACK_DEFAULT_EXPORT__) \n/* harmony export */
});
?
var _App_vue_vue_type_template_id_7ba5bd90_scoped_true___WEBPACK_IMPORTED_MODULE_0__ = __webpack_require__("./src/App.vue?vue&type=template&id=7ba5bd90&scoped=true&");
?
var _App_vue_vue_type_script_lang_js___WEBPACK_IMPORTED_MODULE_1__ = __webpack_require__( "./src/App.vue?vue&type=script&lang=js&");
?
?
?
var _node_modules_vue_loader_lib_runtime_componentNormalizer_js__WEBPACK_IMPORTED_MODULE_2__ = __webpack_require__("./node_modules/vue-loader/lib/runtime/componentNormalizer.js");
?
var component = (0, _node_modules_vue_loader_lib_runtime_componentNormalizer_js__WEBPACK_IMPORTED_MODULE_2__["default"])(
  _App_vue_vue_type_script_lang_js___WEBPACK_IMPORTED_MODULE_1__["default"],
  _App_vue_vue_type_template_id_7ba5bd90_scoped_true___WEBPACK_IMPORTED_MODULE_0__.render, _App_vue_vue_type_template_id_7ba5bd90_scoped_true___WEBPACK_IMPORTED_MODULE_0__.staticRenderFns, false, null, "7ba5bd90", null,/* hot reload */
)

module.exports = function (source) {
  // 這里就是.vue文件的AST
  const loaderContext = this
?
 ?  ...
  // 解析.vue原文件，source對應(yīng)的就是.vue模板
  const descriptor = compiler.parse({
 ?  source,
 ?  compiler: options.compiler || templateCompiler,
 ?  filename,
 ?  sourceRoot,
 ?  needMap: sourceMap
  })
?
 ?  ...
?
  // 使用webpack query source
  let templateImport = `var render, staticRenderFns`
  let templateRequest
  if (descriptor.template) {
 ?  const src = descriptor.template.src || resourcePath
 ?  const idQuery = `&id=${id}`
 ?  const scopedQuery = hasScoped ? `&scoped=true` : ``
 ?  const attrsQuery = attrsToQuery(descriptor.template.attrs)
 ?  // const tsQuery =
 ?  // options.enableTsInTemplate !== false && isTS ? `&ts=true` : ``
 ?  const query = `?vue&type=template${idQuery}${scopedQuery}${attrsQuery}${inheritQuery}`
 ?  const request = (templateRequest = stringifyRequest(src + query))
 ?  templateImport = `import { render, staticRenderFns } from ${request}`
  }
?
 ?  ...
?
  code += `\nexport default component.exports`
  return code
}

{
  source: '<template>\n' +
 ?  '  <div id="box">\n' +
 ?  ' ?  {{ count }}\n' +
 ?  '  </div>\n' +
 ?  '</template>\n' +
 ?  '\n' +
 ?  '<script>\n' +
 ?  'export default {\n' +
 ?  '  props: {},\n' +
 ?  '  data() {\n' +
 ?  ' ?  return {\n' +
 ?  ' ? ?  count: 0\n' +
 ?  ' ?  }\n' +
 ?  '  }\n' +
 ?  '}\n' +
 ?  '</script>\n' +
 ?  '\n' +
 ?  '<style>\n' +
 ?  '#box {\n' +
 ?  '  background: red;\n' +
 ?  '}\n' +
 ?  '</style>\n',
  filename: 'App.vue',
  template: {
 ?  type: 'template',
 ?  content: '\n<div id="box">\n  {{ count }}\n</div>\n',
 ?  start: 10,
 ?  end: 53,
 ?  attrs: {}
  },
  script: {
 ?  type: 'script',
 ?  content: '\n' +
 ? ?  'export default {\n' +
 ? ?  '  props: {},\n' +
 ? ?  '  data() {\n' +
 ? ?  ' ?  return {\n' +
 ? ?  ' ? ?  count: 0\n' +
 ? ?  ' ?  }\n' +
 ? ?  '  }\n' +
 ? ?  '}\n',
 ?  start: 74,
 ?  end: 156,
 ?  attrs: {}
  },
  ....
}

// 編譯前
<div id="box">
  {{ count }}
</div>
?
// 編譯后
var render = function render() {
  var _vm = this,
 ?  _c = _vm._self._c
  return _c("div", { attrs: { id: "box" } }, [
 ?  _vm._v("\n  " + _vm._s(_vm.count) + "\n"),
  ])
}
var staticRenderFns = []
render._withStripped = true
?
export { render, staticRenderFns }

module.exports = function (source) {
  const loaderContext = this
 ?  ...
  // 接收模板編譯核心庫
  const { compiler, templateCompiler } = resolveCompiler(ctx, loaderContext)
?
 ?  ...
?
  // 開啟編譯
  const compiled = compiler.compileTemplate(finalOptions)
?
 ?  ...
?
  // 編譯后產(chǎn)出，code就是render函數(shù)
  const { code } = compiled
?
  // 導(dǎo)出template模塊
  return code + `\nexport { render, staticRenderFns }`
}

export function parseHTML(html, options: HTMLParserOptions) {
  // 存儲解析后的標簽
  const stack: any[] = []
  const expectHTML = options.expectHTML
  const isUnaryTag = options.isUnaryTag || no
  const canBeLeftOpenTag = options.canBeLeftOpenTag || no
  let index = 0
  let last, lastTag
  // 循環(huán) html 字符串結(jié)構(gòu)
  while (html) {
    // 記錄當(dāng)前最新html
    last = html
    if (!lastTag || !isPlainTextElement(lastTag)) {
      // 獲取以 < 為開始的位置
      let textEnd = html.indexOf('<')
      if (textEnd === 0) {
        // 解析注釋
        if (comment.test(html)) {
          const commentEnd = html.indexOf('-->')
          if (commentEnd >= 0) {
            if (options.shouldKeepComment && options.comment) {
              options.comment(
                html.substring(4, commentEnd),
                index,
                index + commentEnd + 3
              )
            }
            advance(commentEnd + 3)
            continue
          }
        }
        // 解析條件注釋
        if (conditionalComment.test(html)) {
          const conditionalEnd = html.indexOf(']>')
          if (conditionalEnd >= 0) {
            advance(conditionalEnd + 2)
            continue
          }
        }
        // 解析 Doctype
        const doctypeMatch = html.match(doctype)
        if (doctypeMatch) {
          advance(doctypeMatch[0].length)
          continue
        }
        // 解析截取結(jié)束標簽
        const endTagMatch = html.match(endTag)
        if (endTagMatch) {
          const curIndex = index
          advance(endTagMatch[0].length)
          parseEndTag(endTagMatch[1], curIndex, index)
          continue
        }
        // 解析截取開始標簽
        const startTagMatch = parseStartTag()
        if (startTagMatch) {
          handleStartTag(startTagMatch)
          if (shouldIgnoreFirstNewline(startTagMatch.tagName, html)) {
            advance(1)
          }
          continue
        }
      }
      let text, rest, next
      if (textEnd >= 0) {
        rest = html.slice(textEnd)
        while (
          !endTag.test(rest) &&
          !startTagOpen.test(rest) &&
          !comment.test(rest) &&
          !conditionalComment.test(rest)
        ) {
          // < in plain text, be forgiving and treat it as text
          next = rest.indexOf('<', 1)
          if (next < 0) break
          textEnd += next
          rest = html.slice(textEnd)
        }
        text = html.substring(0, textEnd)
      }
      // 純文本節(jié)點
      if (textEnd < 0) {
        text = html
      }
      // 截取文本節(jié)點
      if (text) {
        advance(text.length)
      }
      if (options.chars && text) {
        options.chars(text, index - text.length, index)
      }
    } else {
      let endTagLength = 0
      const stackedTag = lastTag.toLowerCase()
      const reStackedTag =
        reCache[stackedTag] ||
        (reCache[stackedTag] = new RegExp(
          '([\s\S]*?)(</' + stackedTag + '[^>]*>)',
          'i'
        ))
      const rest = html.replace(reStackedTag, function (all, text, endTag) {
        endTagLength = endTag.length
        if (!isPlainTextElement(stackedTag) && stackedTag !== 'noscript') {
          text = text
            .replace(/<!--([\s\S]*?)-->/g, '$1') // #7298
            .replace(/<![CDATA[([\s\S]*?)]]>/g, '$1')
        }
        if (shouldIgnoreFirstNewline(stackedTag, text)) {
          text = text.slice(1)
        }
        if (options.chars) {
          options.chars(text)
        }
        return ''
      })
      index += html.length - rest.length
      html = rest
      parseEndTag(stackedTag, index - endTagLength, index)
    }
    if (html === last) {
      options.chars && options.chars(html)
      break
    }
  }
  // 清空閉合標簽
  parseEndTag()
  // 截取標簽，前后推進位置
  function advance(n) {
    index += n
    html = html.substring(n)
  }
  // 解析開始標簽
  function parseStartTag() {
    const start = html.match(startTagOpen)
    if (start) {
      const match: any = {
        tagName: start[1],
        attrs: [],
        start: index
      }
      advance(start[0].length)
      let end, attr
      while (
        !(end = html.match(startTagClose)) &&
        (attr = html.match(dynamicArgAttribute) || html.match(attribute))
      ) {
        attr.start = index
        advance(attr[0].length)
        attr.end = index
        match.attrs.push(attr)
      }
      if (end) {
        match.unarySlash = end[1]
        advance(end[0].length)
        match.end = index
        return match
      }
    }
  }
  // 匹配處理開始標簽
  function handleStartTag(match) {
    const tagName = match.tagName
    const unarySlash = match.unarySlash
    if (expectHTML) {
      if (lastTag === 'p' && isNonPhrasingTag(tagName)) {
        parseEndTag(lastTag)
      }
      if (canBeLeftOpenTag(tagName) && lastTag === tagName) {
        parseEndTag(tagName)
      }
    }
    const unary = isUnaryTag(tagName) || !!unarySlash
    const l = match.attrs.length
    const attrs: ASTAttr[] = new Array(l)
    for (let i = 0; i < l; i++) {
      const args = match.attrs[i]
      const value = args[3] || args[4] || args[5] || ''
      const shouldDecodeNewlines =
        tagName === 'a' && args[1] === 'href'
          ? options.shouldDecodeNewlinesForHref
          : options.shouldDecodeNewlines
      attrs[i] = {
        name: args[1],
        value: decodeAttr(value, shouldDecodeNewlines)
      }
      if (__DEV__ && options.outputSourceRange) {
        attrs[i].start = args.start + args[0].match(/^\s*/).length
        attrs[i].end = args.end
      }
    }
    if (!unary) {
      stack.push({
        tag: tagName,
        lowerCasedTag: tagName.toLowerCase(),
        attrs: attrs,
        start: match.start,
        end: match.end
      })
      lastTag = tagName
    }
    if (options.start) {
      options.start(tagName, attrs, unary, match.start, match.end)
    }
  }
  // 解析結(jié)束標簽
  function parseEndTag(tagName?: any, start?: any, end?: any) {
    let pos, lowerCasedTagName
    if (start == null) start = index
    if (end == null) end = index
    // Find the closest opened tag of the same type
    if (tagName) {
      lowerCasedTagName = tagName.toLowerCase()
      for (pos = stack.length - 1; pos >= 0; pos--) {
        if (stack[pos].lowerCasedTag === lowerCasedTagName) {
          break
        }
      }
    } else {
      // If no tag name is provided, clean shop
      pos = 0
    }
    if (pos >= 0) {
      // Close all the open elements, up the stack
      for (let i = stack.length - 1; i >= pos; i--) {
        if (__DEV__ && (i > pos || !tagName) && options.warn) {
          options.warn(`tag <${stack[i].tag}> has no matching end tag.`, {
            start: stack[i].start,
            end: stack[i].end
          })
        }
        if (options.end) {
          options.end(stack[i].tag, start, end)
        }
      }
      // Remove the open elements from the stack
      stack.length = pos
      lastTag = pos && stack[pos - 1].tag
    } else if (lowerCasedTagName === 'br') {
      if (options.start) {
        options.start(tagName, [], true, start, end)
      }
    } else if (lowerCasedTagName === 'p') {
      if (options.start) {
        options.start(tagName, [], false, start, end)
      }
      if (options.end) {
        options.end(tagName, start, end)
      }
    }
  }
}

// 將AST預(yù)發(fā)轉(zhuǎn)義成render函數(shù)字符串
export function genElement(el: ASTElement, state: CodegenState): string {
  if (el.parent) {
    el.pre = el.pre || el.parent.pre
  }
  if (el.staticRoot && !el.staticProcessed) {
      // 輸出靜態(tài)樹
    return genStatic(el, state)
  } else if (el.once && !el.onceProcessed) {
      // 處理v-once指令
    return genOnce(el, state)
  } else if (el.for && !el.forProcessed) {
      // 處理循環(huán)結(jié)構(gòu)
    return genFor(el, state)
  } else if (el.if && !el.ifProcessed) {
      // 處理條件語法
    return genIf(el, state)
  } else if (el.tag === 'template' && !el.slotTarget && !state.pre) {
      // 處理子標簽
    return genChildren(el, state) || 'void 0'
  } else if (el.tag === 'slot') {
      // 處理插槽
    return genSlot(el, state)
  } else {
    // 處理組件和dom元素
       ...
    return code
  }
}

const compiled = compiler.compileTemplate({
  source: '\n' +
    '<div id="box">\n' +
    '  {{ count }}\n' +
    '  <button @add="handleAdd">+</button>\n' +
    '</div>\n'
});
const { code } = compiled;
// 編譯后
var render = function render() {
  var _vm = this,
    _c = _vm._self._c
  return _c("div", { attrs: { id: "box" } }, [
    _vm._v("\n  " + _vm._s(_vm.count) + "\n  "),
    _c("button", { on: { add: _vm.handleAdd } }, [_vm._v("+")]),
  ])
}
var staticRenderFns = []
render._withStripped = true

export function createCompileToFunctionFn(compile: Function): Function {
  const cache = Object.create(null)
  return function compileToFunctions(
    template: string,
    options?: CompilerOptions,
    vm?: Component
  ): CompiledFunctionResult {
    ...
    // 編譯
    const compiled = compile(template, options)
    // 將genElement階段的產(chǎn)物轉(zhuǎn)化為function
    function createFunction(code, errors) {
      try {
        return new Function(code)
      } catch (err: any) {
        errors.push({ err, code })
        return noop
      }
    }
    const res: any = {}
    const fnGenErrors: any[] = []
    // 將code轉(zhuǎn)化為function
    res.render = createFunction(compiled.render, fnGenErrors)
    res.staticRenderFns = compiled.staticRenderFns.map(code => {
      return createFunction(code, fnGenErrors)
    })
    ...
  }
}