[JavaScript知识库]taro 分包中共用的依赖打包到分包中(Echarts)

Echarts为例：
目录结构：

app.config.json中配置：

echarts为什么会被打包进主包中？

• 虽然引入的ec-canvas组件（echarts-for-weixin）是在分包中使用，但echarts被echarts-for-weixin组件和外部业务组件所依赖，导致Taro认为echarts.js被多个模块所依赖，所以打包到common.js。
• 导致主包大于2M失效

在config/index.js中配置

mini: {
    addChunkPages(pages) {
     //使用到了echarts的页面中注入common依赖
      pages.set("packageA/pages/grades/index", ["packageA/common"]);
    },
    webpackChain(chain) {
      chain.merge({
        optimization: {
       	  //将packageA分包中的依赖打包到 packageA/common.js
          splitChunks: {
            cacheGroups: {
              subpackagesCommon: {
                name: "packageA/common",
                minChunks: 2,
                test: (module, chunks) => {
                  const isNoOnlySubpackRequired = chunks.find(
                    (chunk) => !/\bpackageA\b/.test(chunk.name)
                  );
                  return !isNoOnlySubpackRequired;
                },
                priority: 200,
              },
            },
          },
        },
      });
    },
 }

Taro3中只针对了taro的组件做了注入的处理，对于小程序原生组件没有做注入处理

• 通过taro插件，在ec-canvas中注入依赖

config/index.js

plugins: ["taro-plugin-pinia", [path.resolve(__dirname, "plugin.js")]],

config/plugin.js

const fs = require("fs");
const path = require("path");
export default (ctx, options) => {
  ctx.onBuildFinish(() => {
    console.log("echarts构建hack注入");
    const target = path.join(
      ctx.paths.outputPath,
      "packageA/ec-canvas/ec-canvas.js"
    );
    console.log("触发");
    const data = fs.readFileSync(target, "utf8");
    fs.writeFileSync(target, `require("../common");${data}`);
  });
};