HbuilderX 开发uniapp项目。

问题：Module build failed (from ./node_modules/@dcloudio/webpack-uni-mp-loader/lib/script.js):

报错是因为//#ifdef 条件编译出了问题，

第一种可能 //#ifdef 和 //endif没有成对出现外，

第二种可能是 //#ifdef 之后有其他文本，

第三种可能是//#ifdef 后面有注释

第一行 Module build failed 报错内容是一样的，具体区别注意第二行之后的。
1、没有成对出现：

            //条件编译报错测试
            test(){
                //#ifdef MP-WEIXIN
                uni.showToast({
                    title:"测试代码",
                    icon:"none"
                })
                
            },

区别：Error: Unbalanced delimiter found in string
这句翻译下是说“在字符串中找到不平衡的分隔符”，基本猜猜也能找到错误。

 Module build failed (from ./node_modules/@dcloudio/webpack-uni-mp-loader/lib/script.js):
 Error: Unbalanced delimiter found in string
     at Function.XRegExp.matchRecursive (F:\HbuilderX\HBuilderX.3.2.9.20210927.full\HBuilderX\plugins\uniapp-cli\node_modules\xregexp\lib\addons\matchrecursive.js:186:23)
     at matchReplacePass (F:\HbuilderX\HBuilderX.3.2.9.20210927.full\HBuilderX\plugins\uniapp-cli\node_modules\@dcloudio\vue-cli-plugin-uni\packages\webpack-preprocess-loader\preprocess\lib\preprocess.js:303:27)
     at replaceRecursive (F:\HbuilderX\HBuilderX.3.2.9.20210927.full\HBuilderX\plugins\uniapp-cli\node_modules\@dcloudio\vue-cli-plugin-uni\packages\webpack-preprocess-loader\preprocess\lib\preprocess.js:333:10)
     at preprocessor (F:\HbuilderX\HBuilderX.3.2.9.20210927.full\HBuilderX\plugins\uniapp-cli\node_modules\@dcloudio\vue-cli-plugin-uni\packages\webpack-preprocess-loader\preprocess\lib\preprocess.js:168:10)

2、//#ifdef 后面有文本

            //条件编译报错测试
            test(){
                //#ifdef MP-WEIXIN 小程序执行
                uni.showToast({
                    title:"测试代码",
                    icon:"none"
                })
                //#endif
            },

区别：SyntaxError: Unexpected identifier
这里翻译下说是“意外的标识符”，当时顺手在后面加了个注释，一直报错，差点重装，是挺意外的，编译器要是报个错在哪一行也还好啊。。。

 Module build failed (from ./node_modules/@dcloudio/webpack-uni-mp-loader/lib/script.js):
 SyntaxError: Unexpected identifier
     at new Function (<anonymous>)
     at getTestTemplate (F:\HbuilderX\HBuilderX.3.2.9.20210927.full\HBuilderX\plugins\uniapp-cli\node_modules\@dcloudio\vue-cli-plugin-uni\packages\webpack-preprocess-loader\preprocess\lib\preprocess.js:375:10)
     at testPasses (F:\HbuilderX\HBuilderX.3.2.9.20210927.full\HBuilderX\plugins\uniapp-cli\node_modules\@dcloudio\vue-cli-plugin-uni\packages\webpack-preprocess-loader\preprocess\lib\preprocess.js:379:16)

3、//#ifdef 后面有注释

            //条件编译报错测试
            test(){
                //#ifdef MP-WEIXIN //小程序执行
                uni.showToast({
                    title:"测试代码",
                    icon:"none"
                })
                //#endif
            },

区别：SyntaxError: Unexpected token '}'
习惯在代码后面紧接着写注释的要小心了，//#ifdef 后前外别写。给你报个“}”的错，这下你去找“{ }”吧，越找越迷茫。

 Module build failed (from ./node_modules/@dcloudio/webpack-uni-mp-loader/lib/script.js):
 SyntaxError: Unexpected token '}'
     at new Function (<anonymous>)
     at getTestTemplate (F:\HbuilderX\HBuilderX.3.2.9.20210927.full\HBuilderX\plugins\uniapp-cli\node_modules\@dcloudio\vue-cli-plugin-uni\packages\webpack-preprocess-loader\preprocess\lib\preprocess.js:375:10)
     at testPasses (F:\HbuilderX\HBuilderX.3.2.9.20210927.full\HBuilderX\plugins\uniapp-cli\node_modul

转载：Module build failed (from ./node_modules/@dcloudio/webpack-uni-mp-loader/lib/script.js)_王大快乐鸭的博客-CSDN博客