Syntax Error: TypeError: Cannot set property ‘parent‘ of undefined

起初，我也不过是以为是一个简单的BUG

问题的开始

公司同事让我帮忙打包一个项目的前端包(我是后端)，由于太久没拉过代码，代码冲突了，我重新从云端拉了新的代码，下载依赖，此时并没有任何问题，构建运行的时候，报了这个错

Syntax Error: TypeError: Cannot set property ‘parent’ of undefined

百度结果说vue版本号去掉 ^

^和~的区别

npm官方说明如下：

Tilde Ranges ~1.2.3 ~1.2 ~1

Allows patch-level changes if a minor version is specified on the comparator. Allows minor-level changes if not.

• ~1.2.3 := >=1.2.3 <1.(2+1).0 := >=1.2.3 <1.3.0-0
• ~1.2 := >=1.2.0 <1.(2+1).0 := >=1.2.0 <1.3.0-0 (Same as 1.2.x)
• ~1 := >=1.0.0 <(1+1).0.0 := >=1.0.0 <2.0.0-0 (Same as 1.x)
• ~0.2.3 := >=0.2.3 <0.(2+1).0 := >=0.2.3 <0.3.0-0
• ~0.2 := >=0.2.0 <0.(2+1).0 := >=0.2.0 <0.3.0-0 (Same as 0.2.x)
• ~0 := >=0.0.0 <(0+1).0.0 := >=0.0.0 <1.0.0-0 (Same as 0.x)
• ~1.2.3-beta.2 := >=1.2.3-beta.2 <1.3.0-0 Note that prereleases in the 1.2.3 version will be allowed, if they are greater than or equal to beta.2. So, 1.2.3-beta.4 would be allowed, but 1.2.4-beta.2 would not, because it is a prerelease of a different [major, minor, patch] tuple.

Caret Ranges ^1.2.3 ^0.2.5 ^0.0.4

Allows changes that do not modify the left-most non-zero element in the [major, minor, patch] tuple. In other words, this allows patch and minor updates for versions 1.0.0 and above, patch updates for versions 0.X >=0.1.0, and no updates for versions 0.0.X.

Many authors treat a 0.x version as if the x were the major “breaking-change” indicator.

Caret ranges are ideal when an author may make breaking changes between 0.2.4 and 0.3.0 releases, which is a common practice. However, it presumes that there will not be breaking changes between 0.2.4 and 0.2.5. It allows for changes that are presumed to be additive (but non-breaking), according to commonly observed practices.

• ^1.2.3 := >=1.2.3 <2.0.0-0
• ^0.2.3 := >=0.2.3 <0.3.0-0
• ^0.0.3 := >=0.0.3 <0.0.4-0
• ^1.2.3-beta.2 := >=1.2.3-beta.2 <2.0.0-0 Note that prereleases in the 1.2.3 version will be allowed, if they are greater than or equal to beta.2. So, 1.2.3-beta.4 would be allowed, but 1.2.4-beta.2 would not, because it is a prerelease of a different [major, minor, patch] tuple.
• ^0.0.3-beta := >=0.0.3-beta <0.0.4-0 Note that prereleases in the 0.0.3 version only will be allowed, if they are greater than or equal to beta. So, 0.0.3-pr.2 would be allowed.

When parsing caret ranges, a missing patch value desugars to the number 0, but will allow flexibility within that value, even if the major and minor versions are both 0.

• ^1.2.x := >=1.2.0 <2.0.0-0
• ^0.0.x := >=0.0.0 <0.1.0-0
• ^0.0 := >=0.0.0 <0.1.0-0

A missing minor and patch values will desugar to zero, but also allow flexibility within those values, even if the major version is zero.

• ^1.x := >=1.0.0 <2.0.0-0
• ^0.x := >=0.0.0 <1.0.0-0

总结：如果想要自动修复补丁则使用 Tilde ~,如果不想改变大的版本又想使用较新的版本则使用 Caret ^。

^和~的设置

官网说明

npm config set save-prefix=''	//固定版本
npm config set save-prefix='~'	//自动修复补丁
npm config set save-prefix ^	//较新版本，注意有空格

官方镜像与淘宝镜像

官方镜像

淘宝镜像

• 经过排查，发现前端同事的电脑可以正常运行与构建，代码与我的完全一样
• 我把我本地中的^去掉之后 ，发现居然不报错了，这就奇了个怪了，
• 然后我把同事电脑的依赖删除，重新安装，发现不报错，卧槽？
• 然后我查看了同事电脑的仓库地址是 npm默认的官方镜像，又看了下我的，发现是 淘宝镜像 这就不奇怪了，这就不奇怪了
• 我把本地改成官方镜像 重新带上 ^ 安装测试，发现果然不报错了，那就是说，官方镜像和淘宝镜像有出入
• 后来我又改回了淘宝镜像，版本号也带上了^ ，居然也不报错了
• 淘宝镜像比官方镜像延迟，这是无可厚非的

当我第一次使用淘宝镜像安装依赖的时候，淘宝镜像同步尚未完成，报错原因是因为依赖之间的关系不完善，第二次安装可以成功，说明淘宝镜像已经同步完成。以上仅代表个人看法，如有错误，请指正！