Awesome

babel-upgrade

A tool that tries to automatically update most dependencies, config files, and JavaScript files that require Babel packages directly to Babel 7 (and more in the future).

Usage

Requires nodejs 8 or newer

Run at the root of your git repo:

If using npm < v5.2.0, install npx globally.

# npx lets you run babel-upgrade without installing it locally
npx babel-upgrade --write

# or install globally and run
npm install babel-upgrade -g
babel-upgrade --write

Without the --write (or -w) flag, babel-upgrade will print a diff without writing any changes.

Optionally, add --install (or -i) as well to run yarn or npm after writing the upgrade.

npx babel-upgrade --write --install

Ideas from http://new.babeljs.io/docs/en/next/v7-migration.html (or modify that file if it's missing)

Todos

• Works on Node >= 8 (anything lower isn't supported in v7) (#16)
• Run npm/yarn after updating dependencies (use --install) (#18)
• Update package.json: dependencies and devDependencies to the "latest supported" version.
  • all package renames
    • babel-loader for webpack >=1 (#34)
    • rollup-plugin-babel (#36)
  • Upgrading the same package to the latest version
  • add @babel/core peerDep (7c34cd)

{
  "devDependencies": {
+   "@babel/core": "^7.0.0",
+   "@babel/plugin-proposal-object-rest-spread": "^7.0.0",
+   "@babel/preset-env": "^7.0.0",
+   "babel-loader": "v8.0.0-beta.0"
-   "babel-loader": "6.0.0",
-   "babel-plugin-transform-object-rest-spread": "6.0.0",
-   "babel-preset-env": "^1.0.0",
  },
}

• modify scripts for mocha + @babel/register (e81cf7)

{
  "name": "mocha-scripts-test",
  "scripts": {
-    "test": "mocha --compilers js:babel-register --require babel-polyfill test/*Test.js",
+    "test": "mocha --compilers js:@babel/register --require @babel/polyfill test/*Test.js",
  }
}

• use "babel-core": "^7.0.0-bridge-0" if jest or jest-cli is a dependency (#14)

"devDependencies": {
  "@babel/core": "^7.0.0",
+ "babel-core": "7.0.0-bridge.0",
  "jest": "^22.0.0"
},
"scripts": {
  "test": "jest"
}

• add new @babel/node package if babel-node is used (#14)

"devDependencies": {
  "@babel/cli": "^7.0.0",
+ "@babel/node": "^7.0.0"
},
"scripts": {
  "start": "babel-node a.js"
}

• Handle all nested .babelrc (#14)

- src/
- example/
  - .babelrc // now modifies these too
- test/
  - .babelrc // now modifies these too
- `.babelrc`

• rename config files to swap shorthand form to long form

{
  "presets": [
+   "@babel/preset-env"
-   "env"
  ]
}

• package.json babel key (d123ad)

{
  "babel": {
    "presets": [
+     "@babel/preset-env"
-     "env"
    ]
  }
}

• handle env (e9fc42)

{
  "babel": {
    "presets": [
      "@babel/preset-env"
    ]
  },
  "env": {
    "development": {
      "plugins": [
-       "transform-react-jsx-source",
-       "babel-plugin-transform-react-jsx-self"
+       "@babel/plugin-transform-react-jsx-source",
+       "@babel/plugin-transform-react-jsx-self",
      ]
    }
  }
}

• Modify mocha.opts (e81cf7)

---require babel-register
+--require @babel/register

• Convert comma separated presets/plugins into an array (#37)

{
-  "presets": "env, react",
+  "presets": ["@babel/preset-env", "@babel/preset-react"],

• handle react + flow preset being split. Read if .flowconfig and add it? (#21)

{
  "@babel/preset-react": "^7.0.0",
+  "@babel/preset-flow": "^7.0.0"
}

• Replace Stage presets with individual proposal plugins (#69)

{
-  "presets": ["@babel/preset-stage-3"],
+  "presets": [],
+  "plugins": [
+    "@babel/plugin-syntax-dynamic-import",
+    "@babel/plugin-syntax-import-meta",
+    "@babel/plugin-proposal-class-properties",
+    "@babel/plugin-proposal-json-strings"
+  ]
}

{
-    "@babel/preset-stage-3": "^7.0.0"
+    "@babel/plugin-proposal-class-properties": "^7.0.0",
+    "@babel/plugin-proposal-json-strings": "^7.0.0",
+    "@babel/plugin-syntax-dynamic-import": "^7.0.0",
+    "@babel/plugin-syntax-import-meta": "^7.0.0"
}

• Log when replacing out preset-es2015,16,17,latest as FYI
• Figure out how to change nested .babelrcs into using "overrides" instead
• Monorepo support
• .babelrc.js and other js files with a config like presets, webpack.config.js
• convert only/ignore if necessary
• remove typeof-symbol if using @babel/preset-env + loose
• Update test files that use babel directly (babel-types -> @babel/types, babel-core)
  • Update all requires/imports
  • Update the use of the Babel API (plugins, integrations)
• Modify other config files as we go
• Add to the upgrade guide which parts are autofixable and the command (if we care enough to make this individually runnable too infrastructure wise)
• May need to add a warning on any 3rd party plugins since they might not be compatible
• Handle the differences in plugins in v7 for default/loose/spec
• Should certain parts be generic (replace the string babel-register with @babel/register)? Could be in a Makefile or somewhere else, but it's just find replace.

Philosophy

• Move this into the monorepo when somewhat ready
  • Maybe move into @babel/cli?
  • Or just another package that is intended to be used via npx/globally
• Whenever there is a breaking change in a PR we should also update this tool when possible or at least provide a warning
  • What about with a regression?
• Can be used for non-major bumps too - just for updating to the latest version.
• Include mini-changelog?
• Maybe the version should just reflect the version that it targets?

Development

npm install
npm start