5to6-codemod

5to6-codemod

A collection of codemods that allow you to transform your JavaScript code from ES5 to ES6 using jscodeshift.

Usage

• npm install -g jscodeshift
• npm install 5to6-codemod
• jscodeshift -t node_modules/5to6-codemod/transforms/[transform].js [files]
• Review changes via git diff. Keep what you want, throw it out if you don't. Magic!

Option flags

When executing codemods, you can configure options like so:

jscodeshift -t node_modules/5to6-codemod/transforms/[transform].js [files] --key=value

Recast options

Our transforms will automatically distinguish and pass through Recast config keys via jscodeshift. Official documentation for Recast's configuration can be found here. We currently support the following Recast keys:

• esprima
• inputSourceMap
• lineTerminator
• quote
• range
• reuseWhitespace
• sourceFileName
• sourceMapName
• sourceRoot
• tabWidth
• tolerant
• trailingComma
• useTabs
• wrapColumn

Transforms

• amd - Transforms AMD style modules to ES6 import/export
• cjs - Transforms CommonJS style require() calls to ES6 import statements
  • This transformation accepts the following option flags:
    • hoist: Enables hoisting require statements to the top
• no-strict - Removes "use strict" statements
• exports - Move CommonJS style module.exports statements to ES6 export statements
• named-export-generation - Adds named exports corresponding to default export object keys. Only valid for ES6 modules exporting an object as the default export.
• let - Replace all var calls to use let
• simple-arrow - Replace all function expressions with a body of a sole return statement into arrow functions

Known issues

• Can't automagically figure out when you want to use import * as varName.
• End-of-line comments also missing in many situations
• simple-arrow loses comments in the function expression body