Babel 7 Support

[SamMorrowDrums]

Hi - I don't know if there is a plan to support babel 7, I'm sure it's quite a lot of work but it currently errors when I try it with webpack 4 I get ReferenceError: [BABEL] app/app.js: Unknown option: .visitor. .

When using babel-upgrade --write I get the following changes:

     "reload"
   ],
   "devDependencies": {
-    "babel-cli": "^6.7.5",
-    "babel-core": "^6.26.3",
+    "@babel/cli": "7.0.0-beta.54",
+    "@babel/core": "7.0.0-beta.54",
+    "@babel/plugin-external-helpers": "7.0.0-beta.54",
+    "@babel/plugin-proposal-class-properties": "7.0.0-beta.54",
+    "@babel/plugin-proposal-object-rest-spread": "7.0.0-beta.54",
+    "@babel/preset-env": "7.0.0-beta.54",
+    "@babel/preset-flow": "7.0.0-beta.54",
+    "@babel/preset-react": "7.0.0-beta.54",
+    "babel-core": "^7.0.0-bridge.0",
     "babel-eslint": "^8.2.3",
     "babel-jest": "^22.4.3",
     "babel-plugin-dynamic-import-node": "^1.2.0",
-    "babel-plugin-external-helpers": "^6.22.0",
-    "babel-plugin-transform-class-properties": "^6.24.1",
-    "babel-plugin-transform-object-rest-spread": "^6.26.0",
-    "babel-preset-env": "^1.6.0",
-    "babel-preset-react": "^6.5.0",
     "codecov": "^3.0.1",
     "conventional-github-releaser": "^2.0.2",
     "create-react-class": "^15.6.3",
@@ -81,7 +83,7 @@
     "recompose": "^0.27.0",
     "rimraf": "^2.5.2",
     "rollup": "^0.58.2",
-    "rollup-plugin-babel": "^3.0.4",
+    "rollup-plugin-babel": "^4.0.0-beta.2",
     "rollup-plugin-commonjs": "^9.1.3",
     "rollup-plugin-json": "^2.3.0",
     "rollup-plugin-node-resolve": "^3.3.0",
@@ -93,6 +95,7 @@
     "react": "^15.0.0 || ^16.0.0"
   },
   "dependencies": {
+    "@babel/preset-flow": "7.0.0-beta.54",
     "fast-levenshtein": "^2.0.6",
     "global": "^4.3.0",
     "hoist-non-react-statics": "^2.5.0",

When running npm build I cannot get past the following error (haven't had a lot of time to investigate yet) but certainly, we might need to update a variety of things to properly handle the API changes.

[!] (babel plugin) Error: Cannot find module 'babel-plugin-external-helpers' from '/home/sam/src/github.com/gaearon/react-hot-loader'
- Did you mean "@babel/external-helpers"?
src/index.dev.js
Error: Cannot find module 'babel-plugin-external-helpers' from '/home/sam/src/github.com/gaearon/react-hot-loader'
- Did you mean "@babel/external-helpers"?
    at Function.module.exports [as sync] (/home/sam/src/github.com/gaearon/react-hot-loader/node_modules/resolve/lib/sync.js:43:15)
    at resolveStandardizedName (/home/sam/src/github.com/gaearon/react-hot-loader/node_modules/@babel/core/lib/config/files/plugins.js:101:31)
    at resolvePlugin (/home/sam/src/github.com/gaearon/react-hot-loader/node_modules/@babel/core/lib/config/files/plugins.js:54:10)
    at loadPlugin (/home/sam/src/github.com/gaearon/react-hot-loader/node_modules/@babel/core/lib/config/files/plugins.js:62:20)
    at createDescriptor (/home/sam/src/github.com/gaearon/react-hot-loader/node_modules/@babel/core/lib/config/config-descriptors.js:114:9)
    at items.map (/home/sam/src/github.com/gaearon/react-hot-loader/node_modules/@babel/core/lib/config/config-descriptors.js:69:50)
    at Array.map (<anonymous>)
    at createDescriptors (/home/sam/src/github.com/gaearon/react-hot-loader/node_modules/@babel/core/lib/config/config-descriptors.js:69:29)
    at createPluginDescriptors (/home/sam/src/github.com/gaearon/react-hot-loader/node_modules/@babel/core/lib/config/config-descriptors.js:65:10)
    at alias (/home/sam/src/github.com/gaearon/react-hot-loader/node_modules/@babel/core/lib/config/config-descriptors.js:57:49)

Would be really great if we could begin moving towards babel 7 support. I don't know what it would entail yet - and if all the deps have a working version for that, but certainly it'll only be more important so let me know what your thoughts are.

[SamMorrowDrums]

I should mention I did try running a find replace for `babel-plugin-external-helpers -> @babel/external-helpers" but it didn't do the trick.

[theKashey]

I've got no plans of migrating to babel 7 while it is in beta.
Meanwhile, all the changes to make RHL's babel plugin be babel 7 compatible were made, and one could already use them in a pair, to provision TypeScript, for example.

For Rect-Hot-Loader customer devDependencies means nothing.

[SamMorrowDrums]

@theKashey Thanks for response. Well when I add the Babel plugin to my webpack 4 build (with Babel 7) I get this error: ReferenceError: [BABEL] app/app.js: Unknown option: .visitor. I understand that the dev-deps don't matter, but my build works until I use this plugin - so something isn't working with Babel 7 as far as I can tell.

It's an experimental branch for me, so I'm not in a rush - but I don't know yet what is causing the bug - as I say, the build works just fine without the presets: ['react-hot-loader/babel'], in the babel loader.

[theKashey]

@SamMorrowDrums - I've checked - babel7 did not changed visitor API. Something is wrong with your configuration.

[SamMorrowDrums]

OK I'll close for now - if I find the issue I'll comment, but it's strange that it's only when this plug-in is active that I get the error - so not sure what part of the config is messing with things.

[theKashey]

Babel 7 rc just got released. Reopening the ticket.

[petermikitsh]

It appears some changes might be needed. I'm using Babel 7 (7.0.0-rc.1) and react hot loading is broken.

[theKashey]

Working on this right now as a part of TS hot-reloading.

[theKashey]

@petermikitsh - I could not spot any issues using react-hot-loader with babel 7. Could you shed some light, and share some errors?

I am using configuration from this PR updated to use rc-1, and everything is ok-ish.

[thcolin]

Got same issue with @babel/core^7.0.0 and webpack^4.17.1

Module build failed (from ./node_modules/babel-loader/lib/index.js):
ReferenceError: [BABEL] ./src/index.js: Unknown option: .visitor.

[theKashey]

@thcolin - and only with RHL enabled? Have you updated babel loader to match version 7?
You can also use yarn resolutions to force babel-core to point to version 7 bridge, "fixing" all the not yet migrated tools.

I am afraid, but there is nothing we could fix on our side.

[villesau]

This is what we started to get after updating to babel 7, and only after adding RHL to babelrc:

fe-unit-tests_1   | Module build failed: TypeError: Cannot read property 'push' of null

fe-unit-tests_1   |     at PluginPass.ExportDefaultDeclaration (/frontend/node_modules/react-hot-loader/dist/babel.development.js:83:36)

fe-unit-tests_1   |     at newFn (/frontend/node_modules/@babel/traverse/lib/visitors.js:193:21)

fe-unit-tests_1   |     at NodePath._call (/frontend/node_modules/@babel/traverse/lib/path/context.js:53:20)

fe-unit-tests_1   |     at NodePath.call (/frontend/node_modules/@babel/traverse/lib/path/context.js:40:17)

fe-unit-tests_1   |     at NodePath.visit (/frontend/node_modules/@babel/traverse/lib/path/context.js:88:12)

fe-unit-tests_1   |     at TraversalContext.visitQueue (/frontend/node_modules/@babel/traverse/lib/context.js:118:16)

fe-unit-tests_1   |     at TraversalContext.visitSingle (/frontend/node_modules/@babel/traverse/lib/context.js:90:19)

fe-unit-tests_1   |     at TraversalContext.visit (/frontend/node_modules/@babel/traverse/lib/context.js:146:19)

fe-unit-tests_1   |     at Function.traverse.node (/frontend/node_modules/@babel/traverse/lib/index.js:94:17)

fe-unit-tests_1   |     at traverse (/frontend/node_modules/@babel/traverse/lib/index.js:76:12)