错误:期望file.path导出函数或实例

Question

我为generate-swap-project生成器工具创建了一个名为generate的生成器插件。

让我们先看看：

• https://github.com/generate：用于搭建GitHub项目的新命令行工具和开发人员框架。一个更强大，可合成，功能替代约曼。
• https://github.com/generate/generate：用于搭建GitHub项目的新命令行工具和开发人员框架。Generate提供了Yeoman的健壮性和可配置性，Slush的表现力和简单性，以及比两者都更强大的流控制和可组合性。
• https://github.com/rbecheras/generate-swap-project用于交换项目的生成器(我正在开发的生成器)
• https://github.com/rbecheras/generate-swap-project/tree/1-convert-to-standard-code-style：交换项目的生成器(主分支上的自述)
• https://github.com/rbecheras/generate-swap-project/tree/1-convert-to-standard-code-style：(关于有问题分支的自述)

主分支工作良好，测试在travis和本地dev主机上通过。测试由以下纱线脚本(在主机上)运行：

$ yarn test

但是，在PR #2 Resolve #1 "Convert to ESNext/StandardJS code style"中，我做了以下更改：

• 将ES5代码基转换为ESNext
• 将代码基移到src/lib和src/tests
• 添加了一个只需要generator.js的t根级别的./dist/lib/generator.js文件
• 添加纱线脚本: clear + lint + build + test (cf.关于构建管道的自述部分)

参考到分支1-转换为标准代码样式

测试由以下纱线脚本(在分支1-convert-to-standard-code-style上)运行：

$ yarn travis

或(其别名)

$ yarn pipeline

这是yarn clear && yarn lint && yarn build && yarn test的任务序列

但有一次测试失败( 14次测试通过1次测试失败)，有一个奇怪的错误：Error: expected file.path to export a function or instance

$ yarn pipeline
yarn run v1.3.2
$ yarn clear && yarn lint && yarn build && yarn test
$ yarn rimraf build dist
$ /home/remi/d/dev/generate-swap-project/node_modules/.bin/rimraf build dist
$ yarn lint:esnext
$ yarn standard src/*.js src/**/*.js
$ /home/remi/d/dev/generate-swap-project/node_modules/.bin/standard 'src/*.js' src/lib/generator.js src/tests/plugin.js src/tests/test.js
$ yarn build:lib && yarn build:tests && yarn build:docs
$ yarn babel src/lib/ --out-dir dist/lib --source-maps
$ /home/remi/d/dev/generate-swap-project/node_modules/.bin/babel src/lib/ --out-dir dist/lib --source-maps
src/lib/generator.js -> dist/lib/generator.js
$ yarn babel src/tests/ --out-dir dist/tests --source-maps
$ /home/remi/d/dev/generate-swap-project/node_modules/.bin/babel src/tests/ --out-dir dist/tests --source-maps
src/tests/plugin.js -> dist/tests/plugin.js
src/tests/test.js -> dist/tests/test.js
$ echo WARNING: No documentation build available yet
WARNING: No documentation build available yet
$ yarn mocha dist/tests/**/*.js
$ /home/remi/d/dev/generate-swap-project/node_modules/.bin/mocha 'dist/tests/**/*.js'


  generate-swap-project
    plugin
      ✓ should add tasks to the instance (80ms)
      ✓ should only register the plugin once

  generate-swap-project
    tasks
      ✓ should extend tasks onto the instance
      ✓ should run the `default` task with .build (186ms)
      ✓ should run the `default` task with .generate
    swap-project (CLI)
X =>  1) should run the default task using the `generate-swap-project` name (global install)
      ✓ should run the default task using the `swap-project` generator alias (local generator.js)
    swap-project (API)
      ✓ should run the default task on the generator
      ✓ should run the `swap-project` task
      ✓ should run the `default` task when defined explicitly
    sub-generator
      ✓ should work as a sub-generator
      ✓ should run the `default` task by default
      ✓ should run the `generator:default` task when defined explicitly
      ✓ should run the `generator:swap-project` task
      ✓ should work with nested sub-generators
      ✓ should run tasks as a sub-generator


  15 passing (1s)
  1 failing

  1) generate-swap-project
      swap-project (CLI)
        should run the default task using the `generate-swap-project` name (global install):
    Error: expected file.path to export a function or instance
      at Env.get (node_modules/base-env/lib/file.js:256:11)
      at Env.invoke (node_modules/base-env/lib/env.js:117:19)
      at Generate.<anonymous> (node_modules/base-generators/lib/generator.js:62:30)
      at Generate.getGenerator (node_modules/base-generators/index.js:157:22)
      at Object.exports.process (node_modules/base-generators/lib/tasks.js:127:24)
      at node_modules/base-generators/lib/tasks.js:86:23
      at Array.reduce (<anonymous>)
      at exports.parse (node_modules/base-generators/lib/tasks.js:85:15)
      at Generate.generate (node_modules/base-generators/index.js:490:21)
      at Generate.generate (node_modules/base-generators/index.js:463:23)
      at Context.<anonymous> (dist/tests/test.js:87:11)



error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

这是travis配置

{
  "sudo": false,
  "language": "node_js",
  "node_js": "lts/carbon",
  "script": [
    "npm link",
    "npm install --global generate .",
    "yarn travis"
  ],
  "group": "stable",
  "dist": "trusty",
  "os": "linux"
}

以下是：

• PR #2的特拉维斯菲林建筑
• 和Node LTS/Carbon (v8.y.z)

我不明白为什么这个测试(在CLI模式下运行生成器的测试)在ESNext转换和babel转换之后失败。

我的公关怎么了？

Answer 1

那个bug确实与巴贝尔转移的后果有关。

根目录下的文件generator.js使用CommonJS模块加载，这是全局generate二进制文件直接调用所需的。

这是./generator.js的代码

module.exports = require('./dist/lib/generator')

但是：

• 由于模块./dist/lib/generator.js是./src/lib/generator.js转换的结果，它将生成器导出为默认的匿名函数，
• 由于模块./generator.js是CJS模块，所以使用require()

然后所需的模块不是导出的生成器函数，而是包含属性default的对象；该属性的值是生成器函数。

因此，实现./generator.js的正确方法如下：

module.exports = require('./dist/lib/generator').default

就这样!

这是解决问题的公关，这是PR的路过的特拉维斯建筑。