背景

如果你使用了 element-ui 的el-tabs组件，并且想要单独升级 element-ui 至2.10.0，你会发现，使用了 el-tabs 组件的页面只要打开就卡死。原因是 element-ui~2.10.0 采用了不兼容 vue~2.5.10 的写法。于是我尝试系统性升级 vue 全家桶，这也是为系统赋予更多能力做准备。结果遇到一些报错，这里记录一下。

升级过程

当前版本

vue: 2.5.10

vue-loader: 13.5.0

vue-router: 3.0.1

vuex: 3.0.1

axios: 0.17.1

element-ui: 2.2.2

目标版本

vue: 2.6.10

vue-loader: 15.7.0

vue-router: 3.0.3

vuex: 3.1.1

axios: 0.18.1

element-ui: 2.10.0

报错 1(包版本不匹配)

修改 package.json 中的依赖包版本号之后，npm install一波后就报错了。

Vue packages version mismatch:

- vue@2.6.10
- vue-template-compiler@2.5.10

This may cause things to work incorrectly. Make sure to use the same version for both.
If you are using vue-loader@>=10.0, simply update vue-template-compiler.
If you are using vue-loader@<10.0 or vueify, re-installing vue-loader/vueify should bump vue-template-compiler to the latest.


 @ ./src/router/modules/test/index.js 22:23-67
 @ ./src/router/common.js
 @ ./src/router/index.js
 @ ./src/main.js
 @ multi (webpack)-dev-server/client?http://localhost:9532 webpack/hot/dev-server babel-polyfill ./src/main.js

分析：vue和 vue-template-compiler 两个包的版本不匹配，需要升级vue-template-compile。github 搜索这个包搜不到，最后在 npm 包官网找到了。

解决方案：升级vue-template-compile: 2.6.10

报错 2(vue-loader)

|
| <section>
|     <el-form class="cl-add-form" :model="dataForm" :rules="rules" ref="dataForm" label-width="125px">
|         <el-form-item label="法定节假日名称" prop="name">

 @ ./src/views/backend/enterprise/holiday/add-public-holiday.vue 1:0-97 30:4-35:6 30:81-35:5
 @ ./src/views lazy ^\.\/.*$
 @ ./src/authority/generate-routes.js
 @ ./src/store/modules/user.js
 @ ./src/store/index.js
 @ ./src/main.js
 @ multi (webpack)-dev-server/client?http://localhost:9532 webpack/hot/dev-server babel-polyfill ./src/main.js

 error  in ./src/views/backend/enterprise/holiday/add-special-holiday.vue?vue&type=template&id=09f84cb0&

Module parse failed: Unexpected token (2:0)
You may need an appropriate loader to handle this file type.

分析：经观察，发现可能是不识别 vue 文件或其中某部分，于是从 vue-loader 入手，也在网上查阅了一些资料，需要在 webpack 的plugins中加入vue-loader/lib/plugin。

解决方案：

const VueLoaderPlugin = require('vue-loader/lib/plugin')

plugins: [new VueLoaderPlugin(),
    // 其他插件
    ...
]

报错 3(postcss-loader)

(Emitted value instead of an instance of Error)

 ⚠️  PostCSS Loader

Previous source map found, but options.sourceMap isn't set.
In this case the loader will discard the source map entirely for performance reasons.
See https://github.com/postcss/postcss-loader#sourcemap for more information.



 @ ./node_modules/vue-style-loader!./node_modules/css-loader?{"sourceMap":false}!./node_modules/vue-loader/lib/loaders/stylePostLoader.js!./node_modules/postcss-loader/lib?{"sourceMap":false}!./node_modules/vue-loader/lib?{"loaders":{"css":["vue-style-loader",{"loader":"css-loader","options":{"sourceMap":false}}],"postcss":["vue-style-loader",{"loader":"css-loader","options":{"sourceMap":false}}],"less":["vue-style-loader",{"loader":"css-loader","options":{"sourceMap":false}},{"loader":"less-loader","options":{"sourceMap":false}}],"sass":["vue-style-loader",{"loader":"css-loader","options":{"sourceMap":false}},{"loader":"sass-loader","options":{"indentedSyntax":true,"sourceMap":false}}],"scss":["vue-style-loader",{"loader":"css-loader","options":{"sourceMap":false}},{"loader":"sass-loader","options":{"sourceMap":false}}],"stylus":["vue-style-loader",{"loader":"css-loader","options":{"sourceMap":false}},{"loader":"stylus-loader","options":{"sourceMap":false}}],"styl":["vue-style-loader",{"loader":"css-loader","options":{"sourceMap":false}},{"loader":"stylus-loader","options":{"sourceMap":false}}]},"cssSourceMap":false,"cacheBusting":true,"transformToRequire":{"video":["src","poster"],"source":"src","img":"src","image":"xlink:href"}}!./src/views/iot-supervise/truck/truck-carousel.vue?vue&type=style&index=0&lang=css& 4:14-1577 14:3-18:5 15:22-1585
 @ ./src/views/iot-supervise/truck/truck-carousel.vue?vue&type=style&index=0&lang=css&
 @ ./src/views/iot-supervise/truck/truck-carousel.vue
 @ ./src/views lazy ^\.\/.*$
 @ ./src/authority/generate-routes.js
 @ ./src/store/modules/user.js
 @ ./src/store/index.js
 @ ./src/main.js
 @ multi (webpack)-dev-server/client?http://localhost:9532 webpack/hot/dev-server babel-polyfill ./src/main.js

分析：这里面的错误是关于 postcss-loader 的，只要将 config/index.js 中dev.cssSourceMap设置为 true 即可。

警告 1(svg-sprite-loader)

升级过程中还遇到了一个警告，虽然不影响功能，但是看着还是很难受的。

in ./src/icons/svg/workList.svg

svg-sprite-loader exception. 28 rules applies to D:\coollu\projects\coollu-v3\source-code\v1.0.1\update-elementui-test\src\icons\svg\workList.svg

 @ ./src/icons/svg \.svg$
 @ ./src/icons/index.js
 @ ./src/main.js
 @ multi (webpack)-dev-server/client?http://localhost:9532 webpack/hot/dev-server babel-polyfill ./src/main.js

搜索关键词后，发现网上并没有此类答案。因此我考虑是版本问题，于是升级 svg-sprite-loader 至最新版本4.1.6，解决了这个警告问题。

---

总结

至此升级过程就完成了！顺便一提，系统性升级必须要经过全面测试，否则你难以保证完全向下兼容哦！

原文链接