React native upgrade from babel 6 to babel 7

Question

What would be the steps to upgrade from babel 6 to babel 7 an existing react-native project?

These are the old dependencies:

 "dependencies": {
    .........
    "babel-plugin-transform-runtime": "^6.23.0",
    "babel-preset-latest": "^6.24.1",
    "babel-preset-stage-0": "^6.24.1",
    "babel-register": "^6.24.1",
    "prop-types": "^15.5.10",
    "react": "16.3.1",
    "react-native": "0.55.4",
    "react-redux": "5.0.7",
    "redux": "^4.0.0",
    "redux-actions": "^2.6.1",
    "redux-mock-store": "^1.5.1",
    "redux-persist": "^5.10.0",
    "redux-thunk": "^2.1.0",
  },
  "devDependencies": {
    "babel-eslint": "^8.2.2",
    "babel-plugin-syntax-object-rest-spread": "^6.13.0",
    "babel-plugin-transform-object-rest-spread": "^6.23.0",
    "babel-preset-react-native": "^4.0.0",
    "babel-preset-react-native-stage-0": "^1.0.1",
    "eslint": "^4.18.1",
    "eslint-config-airbnb": "^17.0.0",
    "eslint-plugin-flowtype": "^2.46.1",
    "eslint-plugin-import": "^2.14.0",
    "eslint-plugin-jsx-a11y": "6.1.1",
    "eslint-plugin-react": "^7.4.0",
    "gulp": "^3.9.0",
    "gulp-eslint": "4.0.2",
    "gulp-mocha": "6.0.0",
    "jest": "^23.5.0",
    .....
  },

What steps do you have to follow to make this update? How should the new dependencies looks like?

It is not very clear for me (after reading the babel doc) what I should do to make this upgrade, commands to run and what should be added in dependencies and what in devDependencies.

Also it is not very clear for me what is the difference between babel 6 and babel 7 regarding what is happening with the JS code in a react-native project.

Please don't respond with just links to babel doc or to react-native 0.57 change log.

I would need at least some basic steps to do this upgrade and an example of a package.json of a RN project based on babel 7.

Answer 1

Short answer:

run npx babel-upgrade

(then you can take a look in package.json to check what changed)

Long answer:

For RN 0.57.x after reading the babel and babel-upgrade docs I realized it was enough to have all the old babel dependencies inside devDependencies for my project:

"dependencies": {
    .........
    "react": "16.3.1",
    "react-native": "0.55.4",
 },

"devDependencies": {
   "babel-plugin-transform-runtime": "^6.23.0",
    "babel-preset-latest": "^6.24.1",
    "babel-preset-stage-0": "^6.24.1",
    "babel-register": "^6.24.1",
    "react-native": "0.55.4",
    "babel-eslint": "^8.2.2",
    "babel-plugin-syntax-object-rest-spread": "^6.13.0",
    "babel-plugin-transform-object-rest-spread": "^6.23.0",
    "babel-preset-react-native": "^4.0.0",
    "babel-preset-react-native-stage-0": "^1.0.1",        
    .....
  },

1) I used npx and babel-upgrade (npx is already included in npm versions >= 5.2.0) If you have older npm versions you have to install npx globally.

npx lets you run babel-upgrade without installing it locally.

2) I ran npx babel-upgrade ( without the --write option) to see how the upgrade will affect my package.json deps)

3) I ran npx babel-upgrade --write

4) I set RN version to 0.57.1 and changed the babel-preset dependency from "babel-preset-react-native": "^5", to "metro-react-native-babel-preset": "^0.45.0",and .babelrc configuration to:

{
    "presets": ["module:metro-react-native-babel-preset"]
}

as written in the RN change log instructions.

Now package.json looks like this:

  "dependencies": {
    "react": "16.5.0",
    "react-native": "0.57.1",
    .......
  }

  "devDependencies": {
    "@babel/core": "^7.0.0",
    "@babel/plugin-proposal-class-properties": "^7.0.0",
    "@babel/plugin-proposal-decorators": "^7.0.0",
    "@babel/plugin-proposal-do-expressions": "^7.0.0",
    "@babel/plugin-proposal-export-default-from": "^7.0.0",
    "@babel/plugin-proposal-export-namespace-from": "^7.0.0",
    "@babel/plugin-proposal-function-bind": "^7.0.0",
    "@babel/plugin-proposal-function-sent": "^7.0.0",
    "@babel/plugin-proposal-json-strings": "^7.0.0",
    "@babel/plugin-proposal-logical-assignment-operators": "^7.0.0",
    "@babel/plugin-proposal-nullish-coalescing-operator": "^7.0.0",
    "@babel/plugin-proposal-numeric-separator": "^7.0.0",
    "@babel/plugin-proposal-object-rest-spread": "^7.0.0",
    "@babel/plugin-proposal-optional-chaining": "^7.0.0",
    "@babel/plugin-proposal-pipeline-operator": "^7.0.0",
    "@babel/plugin-proposal-throw-expressions": "^7.0.0",
    "@babel/plugin-syntax-dynamic-import": "^7.0.0",
    "@babel/plugin-syntax-import-meta": "^7.0.0",
    "@babel/plugin-syntax-object-rest-spread": "^7.0.0",
    "@babel/plugin-transform-runtime": "^7.0.0",
    "@babel/preset-env": "^7.0.0",
    "@babel/preset-flow": "^7.0.0",
    "@babel/register": "^7.0.0",
    "babel-core": "^7.0.0-bridge.0",
    "babel-preset-react-native-stage-0": "^1.0.1",
    .....

}

I am not sure if all the new dependencies added by gradle-upgrade are needed but the project builds and runs ok for both android and ios.

If you find a better solution or improvements for this babel update please add a comment or add a new answer, I will be happy to update my answer or accept a new better one.

Sources:

https://github.com/react-native-community/react-native-releases/blob/master/CHANGELOG.md#057

https://github.com/babel/babel-upgrade

For RN 0.58.6 I noticed I do not need so many babel deps. I noticed this creating a new project with a react-native init command.

My package.json file looks now like this:

{
  "dependencies": {
    "react": "16.6.3",
    "react-native": "0.58.6",
    // ....

  },
  "devDependencies": {
    "@babel/core": "^7.0.0-0",
    "babel-core": "^7.0.0-bridge.0",
    "babel-eslint": "^10.0.1",
    "babel-jest": "24.1.0",
    "jest": "24.1.0",
    "metro-react-native-babel-preset": "0.53.0",
    "react-test-renderer": "16.6.3",
    // .... 

  },
  "jest": {
    "preset": "react-native", 
   // ...
  }

}

NOTE: For IOS: I was able to build it in IOS without any react/react-native deps in pod file. I added/re-added those inside Linked Frameworks and Libraries section